Holding Time for Heat Treatment of Steel

[ambot]

Hi, If steel is subjected to heat treatment(hot forming, stress relieving after welding and stress relieving after additional welds) for one hour three times during the fabrication stage, should the test piece subjected to a total holding time of 3 hours to simulate the expected heat treatment or just one hour to simulate for the three heat treatment?

 

[Hush]

How about 1 hour three times?

 

[ambot]

Since we will be ordering the material to manufacturer,if we increase the holding time, additional cost will be added since they will use a higher grade material. Is 3- one hour holding time equal to 1- hour holding time? Would there be changes in mechanical properties between the two or is the two equal as long as the holding time is the same?

 

[arunmrao]

Ideally the test coupon should have been an intefral part of the system,i.e during the hot forming stage itself the test coupon should have been generated. This should be then retained til the end of the processing and then the mechanical properties tested. I assume that you are interested in qualifying the fabrication rather than the steel selected.

If it is not possible to specify this kind of testing procedure isolated test sample would qualify only the steel material, hence a 1 hour soaking would be sufficient.