4130 Contradictions

[masterfabr]

It seems a little perplexing to me that people will bash the use of 4130 for cages yet specify it for suspension components. What takes the most beating,flex,impacts,stress? Is it the cage or the suspension? Since 4130 is so"brittle and prone to fractures" that "it isn't suitable" for a cage then how in the hell is it suitable for suspension components such as a-arms? Hmmmmmmm..........



















Hmmmmmm.......

[whiplash]

I am only guessing but it could be the thickness of the suspension stuff is usually much greater than the cage and therefore not as much of an issue?

[standfast]

4130 is used for cages/structures in the heaviest, fastest, and most expensive off road cars, drag cars, road race cars. I don't think there is an arguement. It just takes better cage design, more difficult welding process, and more money. Who's making the arguement that its not the best option? I can see the arguement that it's overkill for small cars like these but to argue against it is kinda rediculous when you look at it's use in the industry.

[masterfabr]

I agree completely.There's quite few here that say to never use 4130 though.

[dunerocket]

Originally Posted by standfast

4130 is used for cages/structures in the heaviest, fastest, and most expensive off road cars, drag cars, road race cars. I don't think there is an arguement. It just takes better cage design, more difficult welding process, and more money. Who's making the arguement that its not the best option? I can see the arguement that it's overkill for small cars like these but to argue against it is kinda rediculous when you look at it's use in the industry.

The red sections sum it up for me. I didn't use 4130 for anything, including the suspension.

I'm not racing, I'm building for fun. $2.50/foot is better than $8/foot for me. I get to buy extra to cover my mistakes. I don't need to worry nearly as much about the HAZ. If I want the extra strength I can add more bracing or go with a thicker wall.

I could build 2 of everything and still come out saving money....

I intend to have this for many years. My friends buggy, is beginning to crack around many of the welds. His is 4130 and built by a reputable builder. The buggy isn't driven that hard or even often. It's about 6 seasons old.

[masterfabr]

Originally Posted by dunerocket

The red sections sum it up for me. I didn't use 4130 for anything, including the suspension.

I'm not racing, I'm building for fun. $2.50/foot is better than $8/foot for me. I get to buy extra to cover my mistakes. I don't need to worry nearly as much about the HAZ. If I want the extra strength I can add more bracing or go with a thicker wall.

I could build 2 of everything and still come out saving money....

I intend to have this for many years. My friends buggy, is beginning to crack around many of the welds. His is 4130 and built by a reputable builder. The buggy isn't driven that hard or even often. It's about 6 seasons old.

Even reputable builders can learn something from their mistakes.It cracked from poor design not poor material choice.I'm NOT saying to use or not use 4130,just that if it cracked it was not from the material of choice.

[RickS.]

I've always felt that 4130 is used mainly to save weight.
And its being brittle is the trade off that you need to weigh in your own mind. Is it worth it or not? For a minirail with a large sportbike motor, I don't think the weight savings is worth it.

[dunerocket]

Originally Posted by masterfabr

Even reputable builders can learn something from their mistakes.It cracked from poor design not poor material choice.I'm NOT saying to use or not use 4130,just that if it cracked it was not from the material of choice.

I wouldn't completely agree with that. A buggy of the same design and vintage rides with us on occasion. It was not of 4130 and has no cracking... I see him drive it harder than the cracked buggy. There are many variables of which material was one.

I know of no human that could give the absolute definitive answer on why it cracked. A fair evaluation would be if it cracked it may not have been from the material of choice

I do agree that all can learn from their mistakes.

4130 is definitely stronger on a per pound basis, but not on a per dollar basis. The material choice all depends on your goal. For me 1020 works just fine.

[ragingpitbulls20]

Its alot easier to properly heat treat and anneal an a arm than a large chassis. You can do it in a regular oven.

[masterfabr]

Originally Posted by dunerocket

I wouldn't completely agree with that. A buggy of the same design and vintage rides with us on occasion. It was not of 4130 and has no cracking... I see him drive it harder than the cracked buggy. There are many variables of which material was one.

I know of no human that could give the absolute definitive answer on why it cracked. A fair evaluation would be if it cracked it may not have been from the material of choice

I do agree that all can learn from their mistakes.

4130 is definitely stronger on a per pound basis, but not on a per dollar basis. The material choice all depends on your goal. For me 1020 works just fine.

THAT I agree with.