ELEMEN MESIN(RI.1232)

Dosen:Fahmi Mubarok, ST., MSc.Metallurgy LaboratoryMechanical EngineeringITS- Surabaya2008

SambunganSambungan Las

Analisa dan PerhitunganApplikasi

LECTURE IV & VLECTURE IV & V

http://www.its.ac.id/personal/material.php?id=fahmi

Fahmi Mubarok

IV 2Mech. Eng. Dept. ITS Surabaya

Elemen Pengikat (Fasteners, Connectors, Joints): Introduksi

Fasteners

Permanent Detachable

Rivets

Weldments

Metal Stitching

Bolts

Cotter Pins

Keys

Snap Rings

Sambungan permanen: sambungan yang rusak bila dilepas. Sambungan detachable : sambungan yang dapat digunakan atau dilepas se-

waktu-waktu tanpa merusak sambungan itu sendiri.

Fahmi Mubarok

IV 3Mech. Eng. Dept. ITS Surabaya

Sambungan Las: Apliklasi

Fahmi Mubarok

IV 4Mech. Eng. Dept. ITS Surabaya

WeldingWhat is welding?Welding is a fusion process, in which metal parts are heated to the melting point and fused together, usually with a filler of the same material melted along with the parent material.

Temperaturecontrol is themost importantparameterassociated with obtaining agood weld.

Fahmi Mubarok

IV 5Mech. Eng. Dept. ITS Surabaya

Welding

Welding is a very efficient way of joining metals

Welding is labour intensive In a welded structure subject to

fluctuating loads, the strength of the welds determine the strength of the structure

It is important to select the right weld type for the right job

Will perform its intended functionWill have the desired reliability & safetyIs capable of being constructed fabricated inspected transported assembledHas minimum cost

Basic Weld Design ObjectivesAdvantages

Fahmi Mubarok

IV 6Mech. Eng. Dept. ITS Surabaya

Modern Welding Processes

Fahmi Mubarok

IV 7Mech. Eng. Dept. ITS Surabaya

Arc Welding

Electric current flowing through ahigh resistance air gap generates anintense arc with temperatures rangingfrom 6,000 to 10,000 oF.

Arc welding is themost commonmethod used withstructural steelwelding.

Arc Welding Instructions for the Beginner, Lincoln Arc Welding Foundation, Fig. 9&13

Fahmi Mubarok

IV 8Mech. Eng. Dept. ITS Surabaya

Metode Pengelasan: Arc Welding

Shielded Metal-Arc-Welding Process

Fahmi Mubarok

IV 9Mech. Eng. Dept. ITS Surabaya

Metode Pengelasan: Arc Welding

Submerged Arc-Welding Process

Fahmi Mubarok

IV 10Mech. Eng. Dept. ITS Surabaya

Metode Pengelasan: Arc Welding

Flux-Cored Arc-Welding Process

Fahmi Mubarok

IV 11Mech. Eng. Dept. ITS Surabaya

Metode Pengelasan: Arc Welding

Plasma-Arc-Welding Processes

Fahmi Mubarok

IV 12Mech. Eng. Dept. ITS Surabaya

MIG or GMAW

Argon and CO2 are common inert gases used in the MIG process. A mixture of 75% Argon and 25% CO2 (C-25) is also very common.

Continuously fed filler wire makes MIG welding suited to high volume, machine assisted industrial welding applications.

Fahmi Mubarok

IV 13Mech. Eng. Dept. ITS Surabaya

TIG or GTAW

The shielding gas in the TIG process is Helium. This gives rise to the term heli-arc welding.

The TIG process is considered the most precise, most controllable, and cleanest method of welding.

The TIG process can be used to make welds of great strength and quality in thin, light, and dissimilar materials.

Fahmi Mubarok

IV 14Mech. Eng. Dept. ITS Surabaya

Sambungan Las: Metode Pengelasan

Electrogas-WeldingProces

Fahmi Mubarok

IV 15Mech. Eng. Dept. ITS Surabaya

Sambungan Las: Metode Pengelasan

Electroslag-WeldingProcess

Fahmi Mubarok

IV 16Mech. Eng. Dept. ITS Surabaya

Soldering and Brazing

Soldering and brazing are common methods of joining two metals.

Soldering and brazing are not

In brazing, the filler material (silver, brass, bronze) has a melting point above 425 C; and,In soldering, the filler material (lead, tin) has a melting point well below 425 C.Capillary forces for the wetting and flow of the liquid metal into the gaps.Proper fluxes for lowering surface tension, remove oxides, and prevent oxidation.

welding processes because they do not melt the parent material.

In soldering and brazing, the parent metal is heated and the the filler metal is melted into the joint where it cools.

Lead based filler metals are used in soldering and brass based filler metals are used in brazing.

Fahmi Mubarok

IV 17Mech. Eng. Dept. ITS Surabaya

Filler Metals

Filler metal rods and wires are designated by a system established by the American

Welding Society (AWS).

The static strength of a good weld isoften higher than the base material.

Fahmi Mubarok

IV 18Mech. Eng. Dept. ITS Surabaya

Identifikasi Elektrode Pengelasan

Identifikasi tatanama elektrode telah dilakukan oleh AWS (American Welding Sosiety), misalnya:

1/8" E6011dimana 1/8" = diameter elektrode (variasinya antara 1/16" sd 5/16".

E = simbol standar untuk elektrode.60 = kekuatan tarik (tensile strength) , 60.000 psi = 60 ksi.

1 = posisi elektrode. EXX1X: semua posisi

EXX2X: posisi flat dan horisontal

EXX3X: posisi flat

1 = tipe pelapisan eletrode dan arus dalam pengelasan. EXX10: DC+ (DC reverse or DCRP) electrode positive. EXX11: AC or DC- (DC straight or DCSP) electrode negative. EXX12: AC or DC+ EXX13: AC, DC- or DC+

Fahmi Mubarok

IV 19Mech. Eng. Dept. ITS Surabaya

Residual Stresses

The uneven heating and cooling in welding operations gives rise to significant residual stresses in the vicinity of the weld.The residual stresses may distort the part.The residual stresses and discontinuities in a weld have a significant influence on the fatigue life of a part.The fatigue life of a weld is often less than the base material.Residual stresses are influenced by the % carbon found in the material being joined.Residual stresses may be removed by annealing.

Fahmi Mubarok

IV 20Mech. Eng. Dept. ITS Surabaya

AWS

Fahmi Mubarok

IV 21Mech. Eng. Dept. ITS Surabaya

AWS (contd)

Fahmi Mubarok

IV 22Mech. Eng. Dept. ITS Surabaya

Typical Welding Symbol

Fahmi Mubarok

IV 23Mech. Eng. Dept. ITS Surabaya

Typical Welding Symbol (contd)

Fahmi Mubarok

IV 24Mech. Eng. Dept. ITS Surabaya

Sambungan Las: Model Sambungan

Fahmi Mubarok

IV 25Mech. Eng. Dept. ITS Surabaya

Klasifikasi Mode Pembebanan

Welding

SymmetricallyLoaded

EccentricallyLoaded

In Tension In Shear On Plane Out of Plane

Fahmi Mubarok

IV 26Mech. Eng. Dept. ITS Surabaya

Butt Welds

Fahmi Mubarok

IV 27Mech. Eng. Dept. ITS Surabaya

Welds Loaded in Shear

Fahmi Mubarok

IV 28Mech. Eng. Dept. ITS Surabaya

Welds Loaded in Shear (contd)

Fahmi Mubarok

IV 29Mech. Eng. Dept. ITS Surabaya

ExampleThe figure shows a horizontal steel bar, 3/8 in thick, loaded in tension andwelded to a vertical support. Find the load F that will cause a shear stress in the welds of 20 kpsi.

Fahmi Mubarok

IV 30Mech. Eng. Dept. ITS Surabaya

Answer

AF

=

LhA ..7071.0=

Diketahui:= 20 kpsitbar= 3/8hlasan=5/16Llasan = 2

)"22("1657071.0

000.20xxx

Fpsi =

2884.0000.20 inxinlbF =

F = 22.6 kip

ELEMEN MESIN(RI.1232)

Dosen:Fahmi Mubarok, ST., MSc.Metallurgy LaboratoryMechanical EngineeringITS- Surabaya2008

LECTURE VILECTURE VI

Sambungan-Sambuangan Baut dan Mur

-Sambungan Pen- Sambungan Pasak

Selamat Idul Fitri!

Elemen Pengikat (Fasteners, Connectors, Joints): IntroduksiSambungan Las: ApliklasiWeldingWeldingModern Welding ProcessesArc WeldingMetode Pengelasan: Arc WeldingMetode Pengelasan: Arc WeldingMetode Pengelasan: Arc WeldingMetode Pengelasan: Arc WeldingMIG or GMAWTIG or GTAWSambungan Las: Metode PengelasanSambungan Las: Metode PengelasanSoldering and BrazingFiller MetalsIdentifikasi Elektrode PengelasanResidual StressesAWSAWS (contd)Typical Welding SymbolTypical Welding Symbol (contd)Sambungan Las: Model SambunganKlasifikasi Mode PembebananButt WeldsWelds Loaded in ShearWelds Loaded in Shear (contd)ExampleAnswer