Question

A company, which makes forging die wants to improve their steel parts and they contacted you because they heard you know a technology using martensitic transformation to make the surface of their steel product hard. The company selected AISI 1008 steel for their product, but after heat treatment they have no idea how to verify whether the heat treatment did a sufficient job or not.
a. What test will tell whether the heat treatment was good enough?
b. If you have hardness test among the potential testing methods in the list what kind of hardness tests are available and what specific hardness test are you going to suggest to the company? And why?
c. After suggesting the methodology to the company, the company engineer came back with a very low hardness value. What went wrong?
d. What is the solution you want to provide to the company and why?

Answer 1

Answer:

a

Hardness Test

b

The available hardness test are

• Rockwell hardness test
• Vicker's hardness test
• knoop test
• scratch test
• Brinell hardness test e.t.c

I would suggest Rockwell test because

• It has good accuracy
• In this test loads can be applied in 2 stages hence better results are obtained
• it saves time because it testing are faster

c

   Well the following would be the reasons for low hardness value

• It could be because the steel used has a low percentage of carbon
• it could also result from the quenching medium used (e.g water , brine solution e.t.c)

d

In order to solve this problem here are the following ways

• When selecting steel the ones with a carbon percentage 0.3% to 0.8% should be selected
• When quenching the quenching medium should be brine solution  

Explanation:

The reason why the answer to question is hardness test is because the heat treatment was carried out to obtain hardness so if it is great then the heat treatment is good