What type of steel for rear bumper?

[sdnative]

Sorry for the dumb question, and I will preface this with I am not a fabricator or metalurgist. I am having a rear bumper made and the fabricator usually uses what he calls mild steel. I assume this is "A36". I have been doing a little research on the HSLA family of steels and wondering if one of these varieties would be better to use instead. He doesnt have any super fancy tools like a brake, etc just welders, tube benders, etc.. For instance, Slee uses "A656" for his bumpers. Then there is that hot rolled vs cold rolled thing.

Just wanted to get peoples opinions and thoughts about using HSLA steel instead of mild steel. Is the cost much higher? Is it weldable, bendable, etc as mild steel. Is it even worth it? Thanks all.

 

[Pin_Head]

It has ben a while, but the low alloy steels were about 20% more than mild steel and worth it because you can use thinner steel to get the same strength and save weight. They weld fine.

 

[sdnative]

Thanks for the reply. What type do you recommend for this application? I don't mind spending a couple bucks for better material but don't want to double the cost.

 

[Spook50]

This has me curious too. I had been planning to use 3/16" mild to build bumpers when I eventually get the time), so I wonder how much thinner I could use for the same strength if I could use a low alloy steel. Be nice if I can keep from making my truck too much heavier than it already is.

 

[hairy_apple]

"Strength" is somewhat relative too. Metal that flexes and doesn't deform is "strong" for some applications, where metal this is rock hard and won't dent is "strong" for other applications. Keep that in mind when looking at relative "strength" of metals. Hard metal is more brittle and not always best for 4x4 applications where there will be flexing of parts (no so much on a bumper).

 

[cruiserpilot]

I bought rolled steel in 3/16" from Russell Metals.


here is an address to them in San Diego.
Spartan Steel, San Diego, CA
5299 Olive Hill Road
Fallbrook
San Diego
California
92028
Tel 951-659-5868Fax 760-639-3684
Email Address sales@russelmetals.com

my opinion is call them and tell them you want to build a bumper for a truck. They will advise you
correctly I am sure.

 

[Pin_Head]

I don't know enough about them to say. I use Industrial Metal Supply (IMS) and they had some in their remnants pile that were priced about 20% more than HR mild steel, but they didn't have the size I was interested in. IMS has an warehouse in San Diego.

 

[Jetboy]

Building a bumper in something other than mild steel will likely be expensive and time consuming. The reason is that most fab shops have remnants. Lots of them. At any given time my dad's shop will have probably a thousand different remnant pieces in racks. Need 10 inches of 3/4x6" flat bar? It's as easy as walking over and grabbing off the rack. Need the same piece in anything other alloy, you're talking a trip to the steel yard, a cut fee, maybe a wait if they don't stock it, and/or a wait for delivery.

If you're building 100 bumpers then you engineer every part and you don't have to worry about needing a small piece of something mid way through.

If you're just building using steel tube - it's a bit easier because everything is built from the same material.

 

[sdnative]

Thanks for the input. Probably not worth it for a one-off job, but for someone like Slee that sells dozens of these it would be worth it. I guess my engineering ocd is kicking in again

Very good point on the remnants. Same would apply to any trade I imagine.

 

[lalitv74]

Why not use aluminum? I know welding is tougher and kinda hazardous. The benefits would:

lighter weight
more resistant to corrosion

 

[fabriwelder]

I think aluminum would be a poor choice for a bumper. A36 would be the way to go.


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