Machinability of 1040 Steel

[chrisperry12345]

I would like to have a part machined from 1040 steel and I'm wondering if this material has a good machinability rating? Ideally I would like to have a tensile strength of at least 100 KSI for a 5" x 12" x 2.5" sheet, and I'm wondering how I would provide a material call out for this on the drawing? I want to order the material from a supplier without heat treating post-machining, and I am aware that there are several different ways that 1040 can be processed so I'm wondering how to call out the right material.

Thanks,
Chris

 

[redpicker]

I'm not sure how much success you will have tryig to achieve 100 KSI minimum Tensile strength with 1040 steel. With a 2.5" section, it is not going to respond to a quench and temper heat treatment very well. Normailzed, I wouldn't expect much more than 90 KSI tenilse.

As far as machineability goes, it really depends on the machinng operation. Are you talking about turning operations with carbide tools, or intricate milling using HSS tools? Neither one is going to be that difficult for 100 KSI 1040.

rp

 

[chrisperry12345]

So if i'm ordering this material from a supplier, would it usually be normalized? If so, how would I call this out on a drawing? Let's say the machinist gets the drawing and he goes to order the material, at a minimum what information do I need to specify for him? Also, would you recommend a readily available and cost effective steel with a tensile strength of 100 KSI or more that is easily machinable?

 

[redpicker]

Why have you chosed 1040? Generally, steel plate in the thickness you have (2.5") is made from a grade that is suitable for welding, since welding is a common assembly process used for joining these sections. 1040 in not one of the more weldable grades, so I would think you would have trouble sourcing it.

Carbon and low alloy steels in the 100 KSI tensile range are all going to have similar machinability ratings, of course, depending on your machining operation. Is this a high volume job with high-speed machining operations, or a small production run of a specialized part. If it's a small run, I don't think the difference is machinability is going to matter.

As for materials, check out steel suppliers in your area to see what kind of material is available; I really don't have time to run that down for you. You might try ASTM A514, Standard Specification for High-Yield-Strength, Quenched and Tempered Alloy Steel Plate, Suitable for Welding. For 2.5" thick material, this is 100 KSI minimum yield material, so the machinability is going to be considerably less than 1040. But, a supplier that can supply A514 material may have some suggestions for lower strength plate.

rp

 

[TVP]

Chris,

You need to start by finding suitable materials that are available in 2.5" plate or flat bar. Grade 1045 steel is available as plate according to ASTM A830/A830M, but it is to a chemical composition only, not specified mechanical properties. redpicker's suggestion of ASTM A514 is a good one, since this is one product that is widely used and available, and it has defined mechanical properties. Here is an example of a typical stocklist for a large distributor:

http://www.emjmetals.com/StockList.aspx?ptype=products&type=pstk