Dimension vs. Heat Treat 2

[RSimano]

I have a question in regards to Heat Treatment of metals vs. Dimensional characteristics.

Ex. Carbon Steel ASTM A-1011 TY B

.125 +/-.005 THK x 2" +/-.005 Outside Dia.

Under standard heat treatment practices for hardeneing of metals. Will the dimensional characteristics of the parent material alter enough to be a cause of concern for the finished part after it has normalized from heat treatment?

 

[TVP]

Hot-rolled carbon steel according to ASTM A1011 cannot be hardened by thermal processing. Do you know the exact process for "hardening", i.e. time, temperature, etc.

 

[redpicker]

Will the dimensional characteristics of the parent material alter enough to be a cause of concern for the finished part after it has normalized from heat treatment?

The answer is most certianly. You can keep dimensional changes to a minimum by several methods, but a normalizing treatment has the possibility of resulting in more than 0.005" distoriton in 2".

rp

 

[btrueblood]

"Hot-rolled carbon steel according to ASTM A1011 cannot be hardened by thermal processing."

At least not by thermal processing alone, i.e. you would need a carburizing or carbo-nitriding step.

 

[RSimano]

I spoke with the machineist and he corrected me the type steel is type A2. 1850 degrees for 2 hours.

 

[TVP]

While A2 tool steel is an air-hardening grade, meaning that it does not require quenching in water or oil to transform the microstructure to martensite, +/-.005 is too tight a tolerance to expect after heating to 1850 F followed by air cooling.

 

[RSimano]

Thank you for the info.