SAE 1139 2

[rivtim]

I am looking for any information I can get on SAE 1139. Our customer is looking to change a part we currently make from SAE 1018 to SAE 1139.

 

[CoryPad]

SAE J1249 Former SAE Standard and Former SAE Ex-Steels includes 1139, with a footnote stating "These grades remain standard for wire rods."

The composition listed is:
[tt]
SAE No. UNS No. C Mn P, max S, max Si Cr Ni Mo V, min
1139 G11390 0.35–0.43 1.35–1.65 0.040 0.13–0.20 — — — — —[/tt]

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[swall]

Rivtim--just curious about why your customer wants the change. I can understand changing to a .39 carbon steel for higher strength or heat treat ability. But, 1100 series steels contain sulfur for improved machinability. Why is the customer concerned about machinability if you are making the part? Or is he performing a machining operation after he gets the part?

 

[CoryPad]

Good question from swall. 1139 should be a screw machining grade, but I assume rivtim to to be part of a cold forming operation, so they should use 1040.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[rivtim]

Thanks for the input folks! You are both right. I am cold forming but apparently the previous supplier was screw machining and hardening. My customer wasn't aware of the hardening requirement and subsequently is backpedalling now. I am offering 1541 due to the higher mangenese content.

 

[TVP]

If quenching & tempering is required for the final product hardness, why not use 10B21 instead of 1541? 1541 has problems with decarburization, poor microstructure uniformity, high flow stress, low tool life, etc. Is the section size large (> 18 mm)? Will the part operate at a temperature higher than 350 C? If the answer to both of these is no, then 10B21 will produce a better part at lower cost.