I know what the physical differences are (size, finish, etc) but is there any a big difference in shear, compression, or chemistry? I want to reccomend a cost savings to a customer by going to HRS, but I'm not sure if I will be sacrificing anything. These are 1 by 4 by 30 inch parts made from bar stock.
RJT

Cold finished 1018 has higher properties due to cold working (assuming outside is not removed by machining). EMJ catalog says CF1018 has 70K yield as a 1" round bar.

ASTM A36 has about 36K yield (EMJ says 36K min.)

John Oder

Like John said, the yield strengths have a pretty big spread, but the ultimate strengths are about the same.

If the parts aren't likely to get dented or bent, then A36 might be a good choice.

Just had a steel vendor tell me that A36 could have about anything in it. No good specs, the only thing he would gaurantee was if you threw it in the ocean it would sink.

Even the Dead Sea?


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I was born in the sight of water
The whales and the albatross - they are my brothers
Ox

The dead sea is not an ocean.

BTW, aren't a lot of ships made out of A36 or similar?

Just goes to show, all salesmen lie (or they just don't know the truth).

If you want good stuff "like" A36, order up ASTM A516-70 plate and get manufacture's test reports.

John Oder

Any machining to speak of on the part? If so you might not want to recommend A36 HR because your salesman was telling the truth when he said it might have most anything in it. I recently switched from 5/8 HR to 1/2 CF flat on a device I make and sell. Got tired of having the ends ripped off drills and cutters at random due to hard chunks of who knows what embedded in the HR.

I pay about 50% premium per pound for the CF, but the higher yield allowed me to drop the thickness to 1/2 and still have higher strength than before. Overall material cost about 30% more before I account for lost blanks due to bad material and wrecked tools due to the same. Once everything is considered, I make substantially more per hour on the parts and the aggravation factor is way less.

When you buzz the teeth off a near new $45 bimetal bandsaw blade, then trash a $35 carbide endmill an hour later, and repeat on a regular basis, it doesn't take long to figure out the trash that's out there as hot rolled flat today sorta needs to be kept confined to torch and welding work.

One thing I have noticed is that most all the trouble comes from the thicker stuff. I still use some 1/4" HR flat for some other parts and never seem to have any problems with it. I guess its easier to run the half melted stellite valve seats and such into the thicker stuff. Might mess up their rolls if they got too much trash in the thick stuff with nowhere for it to go.

ASTM A36 is the minimum strength designation - 36 KSI
This is the cheapest structural grade and what most rebar, chanels, angles, etc are made from.

The 70 KSI for AISI 1018 is an average strength rating and most of the added strength does come from being cold worked.

Neither one of these designation has very tight chemical specifications and limited consistancy. If you need that, you would need to specify an ASME grade of steel such as ASME SA515 Grade 70.

Having said all of that, most of the places that sell hot rolled steel bar use a steel that is rated A36/M1020.
JR