Outer Limits 4x4 Board

want to make up a new front steering arm and dont want to weld anything. i could machine one up from 4140 (we have some laying around at work). would this be too brittle? i know it work hardens but the only load it will get is end load (not flex) so this shouldnt matter should it?

Andrew

What do you mean by steering arm?

Andrew,

4140 is not brittle. Elongation will be about 15% when tempered within the usual temperature range for this material.

Although the elongation is less than plain carbon steels, given the high tensile strength, much more energy will be required to cause failure and other parts will break first.

4140 is normally supplied hardened and tempered. In this condition it can be machined with carbide tools.

My friend can make me parts out of space grade aluminium, would this be strong enough?

Sorry about the hijack

thanks john.

LuxyBoy wrote:My friend can make me parts out of space grade aluminium, would this be strong enough?

Sorry about the hijack

Sorry I have never heard of that grade.

Steel has an endurance limit, no aluminium alloy does.

That means that aluminium will fail from fatigue eventually, so I doubt that it will be possible to have aluminium steering arms engineered.

how strong are stock tie rod ends or are you going a different route?????

serg

i make all my stuff for my customers out of 4140. never had one complaint. i have winched off mine never bent

giantracing wrote:i make all my stuff for my customers out of 4140. never had one complaint. i have winched off mine never bent

not that im going to, but have you ever welded any 4140? i've heard many mixed opinions on the process. some say dont weld it at all, others say pre-heat to 150-200 and use a Low hydrogen rod, others reccomend pre- heat and mig (s4) or tig (mild filler) and cool in sand.

Andrew.

as a rule i dont weld it. like what are you weld example.... steering dampener bracket to steer arm ... thats ok.

It can be welded.

If stick welding, use low hydrogen. For MIG, normal LW1 is OK.

It has to be pre-heated. The critical thing is to be careful that it does not get too hot from the welding process. Weld a little then let it cool back down to the pre-heat temp, before continuing. Don't build up a lot of weld in one area - alternate where you weld so as not to cause local high temps. Preferably keep checking the temp with crayons or better still with a not contact thermometer.

When the welding is finished ensure it cools slowly.

4140 Brittle???? I thik you may have it confussed. My rear lower trailing arms are 4140 and are welded. They have copped an absolute hiding through competitions and are still straight as.

Having said that I have bent snake racing gear (3140), and wouldn't wish it upon a Jap on ANZAC day.

4140 is strong, even when welded. Many speedway cars ( such as the current Wanless car) have the entire frame done in 4140.

BIG GQ wrote:4140 Brittle???? I thik you may have it confussed. My rear lower trailing arms are 4140 and are welded. They have copped an absolute hiding through competitions and are still straight as.

Having said that I have bent snake racing gear (3140), and wouldn't wish it upon a Jap on ANZAC day.

4140 is strong, even when welded. Many speedway cars ( such as the current Wanless car) have the entire frame done in 4140.

at work ,i have seen a few 4140 shafts fatigue and crack on a welded section when not prepared properly.

andrew

The section where 4140 is welded will never be anywhere near as good as the parent material. If it is welded at a critical section, expect it to fail there.

Trailing arms may have welded ends, but the stresses there are much lower than can be seen mid way along, when the link is hung-up on a rock with up to half the weight of the truck on it.