ASTM A193 Heat Treatment ( 4140,4142,4145,4140H,4142H,4145H)

[MikeAbuhatoum]

thread330-208382
Thank you all for starting this thread, unfortunately B7 & B7M are the most common products in our business but there is not much of information in the ASTM A193spec itself to help you with heat treating your 4140,4142,4145 to B7, however I believe there are few AMS specs that cover the process, anyway we do the mentioned process in a daily basis and it is OR "at least What we do":
1- Austenitize to 1550/1600 for up to 60 Minuets, but never less than 30 minuets.
2- Quench is Mar heated oil.
3- Temper" Immediately after quenching" for another hour( Generally 45-60 Minuets).
4- Thread Roll.......and in some cases we start with thread rolling the product followed by austenitizing, quenching, and tempering.

As long you austenitie, quench, temper.....It is all about timing, and temperature which is easily controlled ! We have never had an issue with this process and I doubt we will ever do.

Best of luck.

Mike Abuhatoum.

 

[arunmrao]

Mike, What is your specific question. You are referencing an old thread and making new comments. Please start a new thread and post your question.


"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[redpicker]

I am not sure the OP has a specific question. I think he is just making comments to the old thread.

However, I believe this deserves comment

...there is not much of information in the ASTM A193spec itself to help you with heat treating your 4140,4142,4145 to B7...

The various standards and specifications often do not detail the processing steps needed to produce the products. The assumption is that the manufacturer possesses the knowledge and skills needed to product the product.

A good product standard will only define the requirements of the product it covers. Often, however, processing requirements get defined in an attempt to insure quality. In this example, ASTM A193 requires B7 materials to be quench and tempered because it is possible to meet the hardness requirements using other heat treatments, but these other treatments may not produce a quality product. The intent is to prevent a manufacturer from producing a product that "meets ASTM A193 B7" but would be unsuitable for use as bolting material, not to tell a manufacturer how to produce bolts that meet B7.

 

[israelkk]

http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-H/download.php?spec=MIL-H-6875H.021377.PDF