Heat Treatment and its Effect on Impact

TestingMazen Aldulaijan

Mohammed AlyahayaMohamed Attia

Kiraben RavinddaranHugo MaganaServer Turedi

Andrew Uy

Introduction

Our experiment consisted of combining 3 in class experiments together:

Cold Work and Annealing of Brass. (Cold work not performed)

Precipitation Hardening of Aluminium Alloy.

Impact Property of Heat-treated Steel.

Objective

The Idea behind this experiment was to observe:

The effect of heat treatment on impact testing.

How heat treatment changes the properties of a metal and its ability to absorb energy.

Engineering Applications

● 3000 ships built in an extremely short time span

● Short timescale from design to manufacture led to several fatal flaws

● 30% of WWII Liberty Ships failed due to brittle fracture

● Protecting drivers and passengers in auto collisions

● Frame crumples like a can instead of separating

● Strengthening bicycle frames

● Drop test with 85 lbs weights dropped from 350mm, 400mm, 450mm

● Folding of frame began at 450mm drop height

List of Apparatuses/Materials- Aluminum 6061

- Brass

- Lindberg GS Heater - Rockwell Hardness Tester Load

Impact Testing Apparatus

- Cold Water

Procedure - Heat Treatment

First experiment:

Annealing temperature of 525°C

Annealing times were 5, 20, 30 minutes at Rockwell test at HRB after each time interval

Second experiment :

● Used Aluminum (6061) Rockwell at HRF.

● Solution heat treat for 60 mins at 525°C then quenched Rockwell Aging for 5, 10, 20 min at 250 then quenched after each,

Rockwell after each time interval.

Procedure - Impact Testing

- Test materials FC Brass, Al-6061 treated and Al-6061 controlled for hardness using the Rockwell Hardness Test

- Use impact testing apparatus to measure force needed to break test specimen.

Results

Results (Continued)

Conclusion/Recommendations•Hardest, strongest and most brittle phase as compared microstructure•Hardness depends on carbon content•Brittle that their ductility and toughness are very low•Metal in the scissors contain 20 times as much carbon and is many times harder.•Ductility and toughness improved by heat treatment•Materials with high strength and ductility posses high impact energy•Energy required to fracture a specimen standard dimension and geometry•Collision, explosion, earthquake example of rapid loading