HMC Internship Report

INTERNSHIP REPORT

INTERNSHIP REPORT AITAZAZ AHSAN 10-ME-04

INTERNSHIP REPORT HEAVY MECHANICAL COMPLEX,TAXILA

Aitazaz Ahsan 10-ME-04 9/7/13 HMC

HMC INTERNSHIP REPORT

AITAZAZ AHSAN 10-ME-04 WAQAS AHMED 10-ME-184 1

In the name of Allah, the most merciful,

The most beneficent



With much effort and time spent, we thank God for being able to complete the internship

in HMC.

We would like to convey our sincere gratitude to our internship advisor Mr.

Muhammad Shoaib, who believed in us and for his kind interest and guidance

without which this endeavor would not have been materialized. Special thanks to

him for his encouragement and support. Our gratitude goes to all workers for

providing us with helpful information and exchanging thoughts, family members

for their financial support and HMC for supporting us in doing our project.

Thank you.

Sincerely,

Aitazaz Ahsan (10-ME-04)

Waqas Ahmed (10-ME-184)



INTRODUCTION TO HMC

Heavy Mechanical Complex Ltd. (HMC)

Heavy Mechanical Complex Ltd. (HMC), Taxila is a major heavy engineering subsidiary of the State Engineering Corporation (SEC) under the Ministry of Industries & Production, Government of Pakistan.

In 1969, General YAHYA KHAN laid the basis of HMC. Then in 1971, HMC started its production. In 1975, Prime minister of Pakistan ZULFIQAR ALI BHUTTO inaugurated the HFF. For some years, these two industries worked separately. But after some years, both were combined because for many works they had need of one another

HMC defines itself as “A technical institute in which all types of machines including Sugar plants, Cement Plants, Road rollers, Over Head Cranes ranging from 0.5 to 50 tons Heat Exchanger boilers, Special Defense parts (i.e., NDC works), Special Vibratory Rollers (which can bear statistically 10 to 12 tons vibratory load) and Pakistan steel works. Some other processes that are also done by HMC are Designing and manufacturing and assembling and installation with the certification of ISO – 9001.

The Heavy Mechanical Complex (HMC), the biggest undertaking of its type in Pakistan, was established in 1976 with Chinese assistance. The Heavy Forge Factory (HFF) at this complex has proved crucial for Pakistan's defense production needs. HMC has the capability for designing, engineering and manufacturing of industrial plants and machinery. HMC has the largest fabrication and machining facilities in the country equipped with Computer Aided Designing (CAD) and can undertake a variety of fabrication / machining jobs on sub-contracting basis. HMC manufactures equipment for hydro-electric power plants, thermal power plants, sulphuric acid plants, industrial alcohol plants, oil & gas processing plants, and chemical & petro-chemical plants, etc. Boilers, cranes, construction machinery, material handling equipment, steel structure, railway equipment, etc. are some of the other products which are produced on regular basis. The company's capabilities include engineering and manufacturing of Sugar Mills ranging between 1,500 - 12,000 TCD (tons of cane crushing capacity per day), Portland Cement Plants of 700- 5,500 TPD (tons per day) module and White Cement Plant of 50 - 1,000 TPD.

HMC have the resources to handle large projects with demanding delivery

schedules. Being the largest and most extensive fabrication and machining facility

equipped with state of the art technology. HMC provide manufacturing services to the

customers.

HMC have gained rich experience in designing and manufacturing of large projects

through collaboration with internationally reputed engineering organizations. All its

processing facilities are in-house including Designing, Fabrication, Machining, Iron and



Steel Castings, Forgings, Heat Treatment, Assembly, Sand Blasting, Painting and

Galvanizing etc.

Working staff

HMC includes the manpower round about 3000 estimated all officers, staff

members and workers.

Shops in Industry

There are several shops in HMC industry.

Almost all of the shops are mentioned below

Machine shop Fabrication shop Forging shop Hydraulic shop Steel foundry Cast iron foundry Heat treatment Galvanize shop Wood working shop (Pattern Shop) Maintenance shop Design department Sales department /(PMD i.e. Project Management Department) Accounts Finance and Administration Power section

Capacity & Specifications

Machining capacity = 500*12 tons

Fabrication and Machining capacity= 1000*12

Total = 500*12 + 1000*12 = 18000 tons per annum

This production capacity can be increased time to time with the extension of man power

and other sources subjecting to sub contractors



Facilities

Design Center

Fabrication

Machining

Steel Foundry

Iron Foundry

Hydraulic Press

Die Forge

Quality Control

Design Center

Established in 1970

About 100 highly qualified and experienced design engineers are engaged in

designing.

Equipped with latest CAD tools (See Hardware & Software).

About 132 node local area network.

Complete design coherence

Integration through management information system.

Design plant & machinery including cement, sugar, thermal & hydro power

plants, chemical, oil & gas processing plants, boilers, pressure vessels, heat

exchangers, cranes, road construction machinery, steel structure, piping, ducting

and other similar heavy engineering equipment.

Quality Control

Inspection and testing is carried out as per the procedures established for ISO 9001 QA

System and ASME Code procedures. The inspection & testing activities are well backed

up with the following facilities:

Non Destructive Examination.



The facility consists of VT, UT, MT, PT, RT (Max 80mm thickness).

Material Testing Lab

The laboratory has the facility for checking chemical analysis of iron and steels, non

ferrous metals by spectrographic and wet chemical methods. Metallographic

Examination, Mechanical testing.

Instrument Calibration Laboratory

This laboratory has facilities for calibration of measuring and testing devices such as

pressure testing gauges, thermocouple, temperature recorders, measuring devices.



PRODUCTION PLANNING &CONTROL

PLANNING SECTION

Marketing Department

Contract with customer

Sale order No given

to product

Designer

Drawing made

Planning Section

List of

Components

made

Material

calculated

Demand for

Request form

Stock

available

Yes No

MMG cell

Purchasing Dpt



GENERAL STORE:

HMC has one big general store which keeps all the parts which are used in

manufacturing products. Raw material parching is done by MMG (Material Management

Group)

DISPATCHING:

Dispatching is “the selecting and sequencing the available jobs to be run at

individual workstations and assignment of those jobs to workers”

A dispatch list is “a listing of manufacturing orders in priority sequence. The dispatch list

is usually communicated to manufacturing detail information on priority, location,

quantity, and the capacity requirement of manufacturing order by operation. Dispatch

lists are normally generated daily and oriented by work center”

Dispatching starts with input as route select and schedule chart. It concerns itself with

starting the process and operation of production. It triggers the starting of the production

activity on the shop floor through release of order and instructions, that are based on

pre-planned times and sequences contained in route sheets and schedule charts.

Dispatching determined the person who will do the job work order and authorizations

are issued to perform the work according to a planned sequence, using pre-scribed

tools and a time schedule. It is the duty of dispatching function to issue requisition for

material and tools on production order.

Dispatching of final product to Client

Dispatching cell is the main cell of PPC of HMC, when a product has been

manufactured and completed, than it is the responsibility of dispatch cell to dispatch the

final completed product to concern person or client.

When a product has been completed and assured by machine shop and fabrication

shop than they inform the dispatch cell, that product is ready for customer and move

order slip sent to dispatch cell.



Now dispatch cell after receiving the move order slip dispatch the final completed

product to concern person.

Packing is done by dispatch cell and wood type packing or other type of packing

depends on the product quality and type. Painting also done by dispatch cell according

to the customer demand.

After surface finishing and painting , dispatch cell give the sale and marketing issue

number to final product and attach the dispatched advice to product which include

information and precautionary measures about product uses and clearance by sale and

marketing department.. Than dispatch cell deliver the final product to relevant customer.

Delivery is two types, first customer himself take his product from HMC dispatch cell, in

this way delivery cost is not include in the manufacturing cost. In second type of delivery

HMC it delivers the product to customer site, in this delivery transportation included in

manufacturing cost.

Sale tax invoice is also made by Dispatch cell.

CTC Fabrication Shop

CTC stands for Central Technical Cell. Basically it is a drawing and planning section of

fabrication shop, in this section different drawings are analyzed and then sent to

different sections of fabrication shop depending upon the job and capacity of the shop.

The main jobs of CTC fabrication are:

Job feeding to shop

Planning

Material check

Observation from manufacturing till sale

In CTC we saw and studied drawings of pressure vessel, over head crane and

reduction furnace stage 5 drawings.



Fabrication Shop

Basically Fabrication Shop is divided into four sections: heavy bay section, medium

bay section, small bay section and marking and layout section

In Fabrication Shop machines and capacities are as follow

Heavy Bay

3000 ton press

1000 ton rolling machine

50 ton capacity cranes

Medium Bay

Shaft cutting Circular saw

Cutting Dia. 1350mm

Shaft welding machine

Height of beam 450mm

Small Bay

2.5 ton press

5 ton bending machine

Marking Layout and Cutting Section



Photo cell cutting machine

Electromagnetic or paper templates are used

CNC cutting machine

A German CNC cutting machine is used for cutting accurate and

complex parts

Plasma arc cutting machine for non ferrous metals

Semi automatic cutting machine

Oxygen and natural gas are used for cutting

Mechanical cutting machine(shearing machine)

Parallel cutting machine

Welding

Mainly welding is done in all bays of fabrication shop. The type of welding used in

fabrication shop is as follows

1. Arc Welding

A process utilizing the concentrated heat of electric arc to join metal by

fusion of the base metal plates with consumable electrode. DC or AC

current sources can be used to produce the arc.

2. Shielded Metal Arc Welding(SMW):

Arc is produced by touching the tip of coated electrode to the surface

of work piece and the moving it to appropriate distance to maintain the

arc. The heat generated melts the electrode tip and it’s coated over the

intermediate area of base metals. Slag is formed to protect the weld

against forming oxides, nitrides. Usually used in construction, ship

building, and pipeline work.

3. Submerged Arc Welding(SAW)

In this technique we shield the metal arc location using a granular flux.

It completely covers the welded region so that too protect against the



oxidation. The remaining flux can be recovered and used again in a

cycle.

4. Electro Slag Welding(ESW)

ESW deposits the weld metal into the weld cavity between two plates

to be joined and space is cooled by water cooled copper shoes to

protect molten slag fro running off. Usually used in special equipment

such as in nuclear industry.

5. Gas Metal Arc Welding(GMAW)

Also known as MIG Welding, Shields the weld zone with an inert gas

like argon, helium or gas mixtures. Deoxidizers present in the weld

makes multiple layers weld possible at the joint.



Advantages of MIG

No slag recovered

High welded metal deposition rate

High speed

Quality weld

Large gaps filled easily

6. Gas Tungsten Arc welding(TIG)

Here tungsten electrode is used as one pole of the arc to generate the

heat required and usually argon is used. It is usually suited to thin

materials producing the excellent quality weld.

NON DESTRUCTIVE LAB

Nondestructive test is used to identify the defects in welding joints in the NDT lab of

HMC .Following the main steps involved in non destructive lab.

NON-DESTRUCTVE TESTING

INTERPRETATION

INDICTION

FALSE NON-RELEVANT

RELEVANT

ACCEPT REJECT



Non destructive test is used for those materials which has sensitive properties, during

the test the characteristics or composition of material does not change.

NON DESTRUCTIVE EXAMINATION FACILITIES

x-ray radiography

Gamma ray radiography

Ultrasonic

Magnetic particle

Liquid penetrant

Eddy current

Spectroscopy

RADIOGRAPHY TECHNIQUES

Following Radiography techniques are in HMC non-destructive lab, but only three

type of radiography are used mostly X-ray ,ultrasonic ,and gamma ray radiography

because other radiography are expensive

X-ray Radiography

Gamma Ray Radiography

Neutron Radiography

Proton Radiography

Xero Radiography

Fluoroscopy



Micro Radiography

Flash Radiography

Auto Radiography

Electron transmit Radiography

WELDING

Defect found in the welding are

Cracks Blow holes

Crack Spatter

Lack of penetration Undercut

Pipes Tungsten inclusion

Porosity Restart of welding

Lack of fusion

Slag inclusions



PENETRANT PRINCIPLES:

1. A penetrant fluid applied to the surface of the piece which is to be tested and is

drawn into any defects.

2. Apply penetrant fluid; allow time for it to soak into cracks.

3. Remove surplus penetrant.

4. Apply a chalky developer provide which soaks up the dye penetrant from any

defects by source capillary action.

5. Surface show stain indict ion any defects.

CAMPARISON & SELECTION OF NDT PROCESSES FOR WELDING

GAS POROSITY

CATEGORY= Processing

Material: Ferrous and non ferrous welds.



NDT METHDS APPLICATION AND LIMITATIONS

Radiography testing Method.

1. Radiography is the most universally used NDT method for detection of gas

porosity in the weldments.

2. The radiography image of a “Round Porosity” will appear as oval shaped spots

with smooth edges, while “elongated porosity” will appear as oval shaped spots

with major axis. Sometimes several time longer then minor axis.

3. Foreign material such as loose scale, flux or splatter will effect validity of test

results.

Ultrasonic Testing Method

1. Ultrasonic testing equipments are highly sensitive, capable of detecting micro

separations.

2. Surface finishing and grain size will affect the validity of the test.

Eddy current Testing Method

1. Normally confined to thin wall welded pipes and tube.

2. Penetration restricts testing to a depth of more than one quarter inch.

Liquid Penetrant Testing Method

a. Normally confined to in processes control of ferrous and non ferrous

welds.

b. Liquid penetrant testing is like magnetic particle is restricted to surface

evaluation.

c. Extreme condition must be exercised to prevent any cleaning material and

liquid penetrant materials from becoming entrapped and contaminating the

rewelding operation.

Magnetic particle Testing Method



Normally used to detect gas porosity .Only surface porosity would be evident.

Near surface porosity would not be clearly defined, since indications are neither

strong nor pronounced

MACHINE SHOP

HMC has following machines

Gear shaper machine

Straight bevel machine

Gear hobbing machine

Vertical turret lathe machine

Horizontal lathe machine

Horizontal vertical slope type boring and milling machine.

Universal boring, milling, facing, threading, taping machine.

Plano milling machine.

Horizontal boring machine.

Redial drilling machine.

Column drilling machine.

Gear shaper tool machine

Slotting machine

BVT boring vertical turret machine

Face plat lathe machine.

Double housing planner

Vertical milling machine.



Gear Shaper

A gear shaper is a machine tool for cutting the teeth of internal or external gears. The

name shaper relates to the fact that the cutter engages the part on the forward stroke

and pulls away from the part on the return stroke, just like the clapper box on a planer

shaper. To cut external teeth, a different machine called a hobbing machine can be

used.

Spur Gears

They connect parallel shafts, have involute teeth that are parallel to the shaft and can

have internal or external teeth. They cause no external thrust between gears. They are

inexpensive to manufacture. They give lower but satisfactory performance. They are

used when shaft rotates in the same plane.

Helical Gears

Helical gears connect parallel shifts but the

involute teeth are cut at an angle to the axis of

rotation. Two mating helical gears must have

equal helix angle but opposite hand. They run smoother and more quietly. They have

higher load capacity, are more expensive to manufacture and create axial thrust. They

have longer and strong teeth. They can carry heavy load because of the greater surface

contact with the teeth. The efficiency is also reduced because of longer surface contact.

The gearing is quieter with less vibration.

Internal Gears:

Internal gears are hollow. The properties and teeth shape is similar as of external gears

except that the internal gear had different addendum and dedendum values modified to

prevent interference in internal meshes. They are designed to accommodate a wide

range of equipment. These are ideal and cost effective. The teeth are cut into the inside



diameter while the outside diameter is smooth. These gears are available only in brass.

Internal gear offers low sliding and high stress loading. They are used in planetary

gears to produce large reduction ratios.

When choosing a mating gear the difference between the number of teeth of girth gear

and the pinion should not be less than 15. Their non-binding tooth design ensures

smooth, quiet operation. They are used to transmit rotary motion between parallel

shafts, the shaft rotating in the same direction as the arrangement.

Worm Gears:

The Worm gear is the heart of most mills and kiln drive system. They can't be

used in spare parts inventory. They are also used in steel industry, sugar industry,

paper and pulp industry. The girth gear has been preferred over the gearless drives due

to their lower initial cost, simplicity to install, operate and maintain.

Hobbing:

Hobbing is a machining process for making gears, on a hobbing machine, which is a

special type of milling machine .The teeth or spines are progressively cut into the work

piece by a series of cuts made by a cutting tools called a hob. Compared to other gear

forming processes it is relatively inexpensive but still quite accurate, thus it is used for a

broad range of parts and quantities. It is the most widely used gear cutting process for

creating spur and helical gears and more gears are cut by hobbing than any other

process since it is relatively quick and inexpensive.



Turning:

Milling:



HEAT TREATMENT AND TTC (TECHNICAL TRAINING CELL)

Training program subject:-

Study of process involved in the heat treatment of

different material according to the required hardness

Heat Treatment – The Processes

Annealing

Normalizing

Hardening

Surface

Full

Case

Tempering

Stress releasing

Carburizing

Gas

Pack

Phosphating.

Heat treatment:-

Heat Treatment is the controlled heating and cooling of metals to alter

their physical and mechanical properties without changing the product shape.

Annealing: Used variously to soften, relieve internal stresses, and improve

machinability and to develop particular mechanical and physical properties. Annealing is

the process of slowly raising the temperature above the 3rd critical temperature. It is

held at this temperature for sufficient time as per requirement. It is then slowly cooled

down in a furnace. Usually used for high plane carbon steel.



Normalizing:

Normalizing is the process of raising the temperature above 3rd critical temperature

range. Usually up to 900 degree centigrade. It is held at this temperature and then

removed form the furnace and cooled at room temperature under natural convection.

The resulting material is soft; the degree of softness depends on the actual ambient

conditions of cooling. This process is considerably cheaper than full annealing since

there is not the added cost of controlled furnace cooling. Usually used for alloy steel.

Hardening:

Flame Hardening: A high intensity oxy-acetylene flame is applied to the selective

region. The temperature is raised high. The "right" temperature is determined by the

operator based on experience by watching the color of the steel. The overall heat

transfer is limited by the torch and thus the interior never reaches the high temperature.

The heated region is quenched to achieve the desired hardness. Tempering can be

done to eliminate brittleness.

Induction Hardening: In Induction hardening, the steel part is placed inside a electrical

coil which has alternating current through it. This energizes the steel part and heats it

up. Depending on the frequency and amperage, the rate of heating as well as the depth

of heating can be controlled. Hence, this is well suited for surface heat treatment. The

Induction and flame hardening processes protect areas exposed to excessive wear.

Items that we induction harden:

Spur Gears and Spur Pinions ,Helical Gears and Helical Pinions ,Sprockets ,Internal

Gears ,Bevel Gears ,Shafts and Pins ,Rails and Racks ,Wheels and Rollers Sheave

Wheels ,Links ,Axle Boxes ,Bushes.

Tempering: Tempering is a process done subsequent to quench hardening. Quench-

hardened parts are often too brittle. This brittleness is removed by tempering.

Tempering results in a desired combination of hardness, ductility, toughness, strength,

and structural stability. Tempering is done immediately after quench hardening. When



the steel cools to about 40 ºC (104 ºF) after quenching, it is ready to be tempered. The

steel can be heated to a temperature of 400 to 700 ºC (752 to 1292 ºF) that results in a

softer structure having more ductility and toughness.

Stress Relief: stress releasing is used to reduce residual stresses in large castings,

welded parts and cold-formed parts. Such parts tend to have stresses due to thermal

cycling or work hardening. Parts are heated to temperatures of up to 600 - 650 ºC (1112

- 1202 ºF), and held for an extended time (about 1 hour or more) and then slowly cooled

in still air.

Carburizing: Carbon diffusion (carburizing) produces a higher carbon steel composition

on the part surface. Carburizing, also known as carburization, is a heat treatment

process in which iron or steel is heated in the presence of another material (but below

the metal's melting point) which liberates carbon as it decomposes. The outer surface or

case will have higher carbon content than the original material. When the iron or steel is

cooled rapidly by quenching, the higher carbon content on the outer surface becomes

hard, while the core remains soft and tough. Carburization used a direct application of

coal packed onto the metal, packed in a box which is heated in a furnace. In gas

carburizing, drop wise kerosene oil is drip into the chamber containing metal to be

carburized.

Phosphating: Phosphate coatings are used on steel parts for corrosion resistance,

lubricity, or as a foundation for subsequent coatings or painting. Phosphate conversion

coatings can also be used on aluminum, zinc, cadmium, silver and tin.

Chemical used is 10:1 Gronodean and water.

Electric Furnaces:-

1. Car bottom furnace

Max. Temp = 950oC

Size =900 x 700 x 1800

Plotter and temperature indicator is attached with it.



2. Box type air furnace

It is small and large.

Max. Temp = 950oC

Size =600 x 500 x 1200

3. Pit type tempering furnace

Max. Temp = 950oC

Size =450 x 450 x 950

4. Salt bath furnace

Small, medium, large

Temp = 550-650oC

Size =300 x 400 x 500

Temp = 700-900oC

Size =300 x 400 x 800

Temp = 1050-1270oC

Size =200 x 300 x 800

5. Flame quenching plant

Vertical: φ1200 x 600

Horizontal: φ 450 x 2400

6. High frequency induction machine

Description: It is in isolated room, it uses 10,000 volts. It have a copper ring that

induct heat to the component’s external part, it have a mechanism of movement of



job and quenching. Room is provided with oil and water drum for the purpose of

quenching.

7. Cleaner

Description: It is use to wash salt from metal surface after sand bathing.

8. Shot blasting

Description: It is used for the purpose of cleaning the surface of material subjected

to heat treatment.

9. Electric gas carburizing furnace

Description:

Temp = 950oC

Size =φ 300 x 600

10. Electric tempering furnace

Temp = 650oC

Size =φ950 x 1220

11. Salt bath

Size =2000 x 2000 x 1400

12. Water quenching tank

Size =1500 x 3000 x 3000



Introduction to Casting and Pattern Shop

Materials Processing has been defined as the science and technology by which

a material is converted in to a useful shape with a structure and properties that

are optimized for the proposed service environment.

Various operations and processes are involved in the manufacture of products

and components and these are classified in to four basic families as shown in

figure.



The material removal processes begin with an over size piece and remove

material to leave a desired shape. While these processes have often been

referred to as machining, that term is generally used to describe the mechanical

cutting of materials. It also means removal by all other means, including

chemical, thermal, and physical processes.

Casting processes exploit the fluidity of a liquid as it assumes the shape of a

prepared container and solidifies upon cooling.

Deformation processes exploit the ductility of certain materials, most notably

metals, and produce the desired shape by mechanical rearrangement, or

plasticity.

Consolidation processes are those processes that put pieces together, and

include welding, brazing, soldering, adhesive bonding, and mechanical fasteners.

Powder metallurgy is the manufacture of the desired shape from particulate

material and involves aspects of casting, forming, and consolidation.

Each of the various families has distinctive advantages and limitations, and the

various processes within the families have unique characteristics.

Cast products can have extremely complex shapes but also have structures

that are produced by solidification and are subject to associated defects, such as

shrinkage and porosity.

Material removal processes are capable of outstanding dimensional precision

but produces scrap as material is cut away to produce the desired shape.

Deformation processes can have high rates of production but generally require

powerful equipment and dedicated tools or dies.

In casting processes, a solid material is first melted, heated to proper

temperature, and sometimes treated to modify its chemical composition.

The molten material, generally metal, is then poured into a cavity or mold that

contains it in the desired shape during solidification.



Thus, in a single step, simple or complex shapes can be made from any

material that can be melted. The resulting product can have virtually any

configuration the designer desires.

In addition, the resistance to working stresses can be optimized, directional

properties can be controlled, and a pleasing appearance can be produced.

Cast parts range in size from a fraction of an inch and a fraction of an ounce

(such as the individual teeth on a zipper), to over 30 ft (10 m) and many tons

(such as the huge propellers and stem frames of ocean liners).

Moreover the casting processes have distinct advantages in the production of

complex shapes, parts having hollow sections or internal cavities, parts that

contain irregular curved surfaces (except those made from thin sheet metal), very

large parts, and parts made from metals that are difficult to machine.

Because of these features, casting is one of the most important of the

manufacturing processes.

CAST IRON & STEEL FOUNDARY

Basic Requirements of Casting Processes

Six basic requirements are associated with most casting processes.

1- A mold cavity, having the desired shape and size, must be produced with due

allowance for shrinkage of the solidifying material. Any geometrical feature

desired in the finished casting must exist in the cavity. Consequently, the mold

material must be able to reproduce the desired detail and also have a refractory

character so that it will not contaminate the molten material that it will contain.

2- A melting process must be capable of providing molten material not only at the

proper temperature, but also in the desired quantity, with acceptable quality, and

within a reasonable cost.

3- A pouring technique must be devised to introduce the molten metal into the

mold. Provision should be made for the escape of all air or gases present in the

cavity prior to pouring, as well as those generated by the introduction of the hot



metal. The molten material is then free to fill the cavity, producing a high-quality

casting that is fully dense and free of defects.

4- The solidification process should be properly designed and controlled.

Castings should be designed so that solidification and solidification shrinkage

can occur without producing internal porosity or voids. In addition, the molds

should not provide excessive restraint to the shrinkage that accompanies cooling.

If they do, the casting may crack when it is still hot and its strength is low.

5- It must be possible to remove the casting from the mold (i.e., mold removal).

With single-use molds that are broken apart and destroyed after each casting,

there is no serious difficulty. With multiple-use molds, however, the removal of a

complex- shaped casting may present a major design problem.

6- After the casting is removed from the mold, various cleaning, finishing, and

inspection operations may be required. Extraneous material is usually attached

where the metal entered the cavity, excess material may be present along mold

parting lines, and mold material often adheres to the casting surface. All of these

must be removed from the finished casting.

Casting Terminology

Before proceeding with the process fundamentals, it is helpful if we first

become familiar with a variety of casting terms. Figure 13-2 shows the cross

section of a two-part sand mold and incorporates many features of a typical

casting process.

The process starts with the construction of a pattern, an approximate

duplicate of the final casting. The molding material is then packed around

the pattern and the pattern is removed to produce a mold cavity.

The flask is the box that contains the molding aggregate.

In a two-part mold, the cope is the name given to the top half of the pattern,

flask, mold, or core.

The drag refers to the bottom half of any of these features.

A core is a sand shape that is inserted into the mold to produce the internal

features of a casting, such as holes or passages for water cooling.



A core print is that region added to the pattern, core, or mold that is used to

locate and support the core within the mold.

The mold material and the core then combine to form the mold cavity, the

shaped hole into which the molten metal is poured and solidified to produce

the desired casting.

A riser is an extra void created in the mold that will also fill with molten metal.

It provides a reservoir of material that can flow into the mold cavity to

compensate for any shrinkage that occurs during solidification.

The gating system is the network of channels used to deliver the molten

metal to the mold cavity.

The pouring cup (or pouring basin) is the portion of the gating system that

initially receives the molten metal from the pouring vessel and controls its

delivery to the rest of the mold.

From the pouring cup, the metal travels down a sprue (the vertical portion of

the gating system), then along horizontal channels, called runners, and

finally through controlled entrances, or gates, into the mold cavity.

Additional channels, known as vents, may be included to provide an escape

for the gases that are generated within the mold.

The parting line or parting surface is the interface that separates the cope

and drag halves of a mold, flask, or pattern and also the halves of a core in

some core-making processes.

Draft is the taper on a pattern or casting that permits it to be withdrawn from

the mold. The mold or die used to produce casting cores is known as a core

box.



Types of patterns

1. Wooden patterns

2. Metallic patterns

1. Wooden patterns are used when amount of castings are low and we need rough

finishing. They are not expensive.

2. Metallic patterns are used when amount of castings are very large and we need

fine surface finish. These are very expensive. Cost is compensated by the no. of

castings.



Forging Shop

Forging is term applied to a family of processes where deformation is induced by

localized compressive forces. The equipment can be manual or power hammers,

presses, or special forging machines. While deformation can be done in the hot, cold,

warm, or isothermal mode.

Forging is the oldest known metalworking process and it has been an effective method

of producing many useful shapes. High-powered hammers and mechanical presses

have replaced strong arm, hammer, and anvil, Modern metallurgical knowledge helps

the craftsman in controlling the heating and handling of the metal

The term forging usually implies hot forging done above the recrystallization

temperature Forging is a common term used in manufacture of semi-completed forms,

pressed from hot or cold metal blanks in open or closed dies, by the use of force on the

work piece. The amount of forging may be very less or quite large, and can be made of

brass, steel, or other metals. In hot forging process, the billet is heated to a

temperature, which is dependent upon the material being forged.

The forging material may be

– Drawn out to increase its length and decrease its cross section,

– Upset to decrease the length and increase the cross section,

– Squeezed in closed impression dies to produce multidirectional flow.

Common forging processes include:

– Open-die drop-hammer forging

– Impression-die drop forging

– Press forging

– Upset forging



Forging Applications

Forged parts vary in size ranging from a few pounds up to 300 tons, and can be termed

into small, medium, and heavy forgings. Small parts include tools such as chisels, and

tools used in cutting and carving wood. Medium forgings include axles of cars, small

crankshafts, connecting rods, levers and hooks. Heavier forgings are shafts of power

plant generators, ships, turbines, columns of presses and rolls for rolling mills.

Methods of Hot Forging

Open Die Forging:

Heated metal parts are shaped between a top die attached to a ram, and a base die

connected to a hammer anvil or press bed. Metal parts are heated above their

recrystallization temperatures, and steadily shaped into the selected configuration

through the hammering or pressing of the work piece. The metal is never wholly

confined or restricted in the dies. The majority of open die forgings are formed on flat

dies. Although the open die forging method is often related with larger, simple shaped

parts such as bars, blanks, rings, hollows or spindles, it can be considered the final

option in custom intended metal components. Long life and high intensity parts,

optimized in terms of both structural integrity and mechanical properties, are produced

in different sizes, ranging from a few pounds to hundreds of tons in weight.

Closed Die or Impression Forging:

In this process the hot metal is trapped in recessed impressions, and is hydraulically or

mechanically pressed to a desired shape. Often two or more progressive impressions

are used, normally in conjunction with one or more preforming operations. A negative

image of the component to be made is sunk into a block or pair of blocks. The die set is

keyed or clamped into a press or hammer, which supplies the energy for the



deformation. This method is used to make cutlery, automotive parts, and parts for

aircraft engines.

Impression Die Forging Process Operations

In the simplest example of impression die forging, two dies are brought together and the

work piece undergoes plastic deformation until its enlarged sides touch the side walls of

the die. Then, a small amount of material begins to flow outside the die impression

forming flash that is gradually thinned. The flash cools rapidly and presents increased

resistance to deformation and helps build up pressure inside the bulk of the work piece

that aids material flow into unfilled impressions.

. The impression in the ram-operated "heading tool" is the equivalent of a hammer or

press top die. The "grip dies" contain the impressions corresponding to the hammer or

press bottom die. Grip dies consist of a stationary die and a moving die which, when

closed, act to grip the stock and hold it in position for forging. After each work stroke of

the machine, these dies permit the transfer of stock from one cavity to another in the

multiple-impression dies.

Hammer Forging

A forging method in which the part is distorted by recurrent blows using a forging

hammer, between impression and flat dies. This procedure is also called drop forging.



Forging Equipment

Forging Machine:

A forging machine includes an anvil mass and a ram block, to be released and struck

against it, between which forging is carried out. The machine comprises of a damping

mass, which experiences the blow and moves in a large amplitude of motion in

comparison with the amplitude of motion of the anvil mass, to damp the blows

conducted from the anvil mass to the stationary foundation of the machine.



Hydraulic Forging Press:

It consists of the press, the hydraulic intensifier, and the auxiliary water tank. A piece of

work is compressed between the dies. Numerous shapes of dies may be used. The

press head is forced down by hydraulic pressure on the ram in the cylinder, and is lifted

by steam pressure under the two pistons in the cylinders. The vertical motion of the

press head is directed by the four columns which hold the press firmly against distortion.

Water pressure is exerted through the pipe from the steam intensifier. Steam admitted

under the piston imparts the pressure to the water.

INSPECTION

Inspection is a process in which the material is just visually Checked by using many

apparatus like Verneir Caliper, Micro meter screw gauges, Tapes, Compasses etc.

When this is done, then a report is prepared containing all the references with respect to

that the material was passed out from the inspection stage and this is a necessary step

to assure the quality of the product. And is done where the status of the

manufacturing industry is to be maintained and the Quality of the manufactured

product is to kept up to the standards. The working process starts with agreement

between purchaser and manufacture, the manufacture provides Preformat Invoice

(PI) to the purchaser which explains the equipment specification and related price.

Then the purchaser issues the Purchase Order (PO) which confirming the

preformat invoice. Before start of manufacturing, the purchaser must provide

equipment inspection and test plan (ITP) to the manufacture. The ITP identifies all

inspection points for purchaser inspector. Then the manufacture needs to prepare the

project quality control plan based of this inspection and test plan. The manufacture

notifies purchaser inspector in advance to attend to her factory for witnessing the

inspections and tests. The communication and coordination channel between

manufacture, purchaser inspector and purchaser are agreed in the Pre-inspection

meeting (PIM).Based the international practice manufacture sends her notification



to the purchaser, and purchaser reviews the notification and after her approval sends

to the inspector. Then the inspector will be attended in the in manufacture shop

to witness the test or inspection. The purchaser inspector will send his/her inspection

visit report to the purchaser. Purchaser can assign his/her own inspector which is her

own direct employee or hire a third party inspection agency to carry out inspection.

Inspection and test plan has tabular format and its content extracted from construction

code. In each row of the table there is quality control and inspection requirement and

determine which party is responsible for control and inspection.

There are three parties in ITP, Manufacture, Third Party Inspector (TPI) and Client

or purchaser.

Normally the table accommodates 3 sections as following:

Before Manufacturing

During Manufacturing

Final Inspection

SUBMITTED TO : Mr.Shoaib (Instructing Manager)

Submitted By : Aitazaz Ahsan (10-ME-04)

Waqas Ahmed (10-ME-184)



Mechanical Engineering Department

University of Engineering and Technology

Taxila.

Documents

HMC Internship Report