4130 and 4140 comparison
4130 and 4140 comparison
(OP)
I am machining a set of steering tie rods out 4140 for a customer. He wanted 4130 but I was out, I recommended 4140 and he agreed. How do these two metals compare ??? These tie rods are for a Off-road desert racing truck, extreme duty, should I just order some 4130 ?





RE: 4130 and 4140 comparison
RE: 4130 and 4140 comparison
RE: 4130 and 4140 comparison
My seat of the pants feeling is that either alloy would suffice for automotive tie rods, even as-rolled or in a normalized condition. For severe applications maybe consider a tempered martensite structure with a generous tempering temperature for the higher toughness. Check crankshaft con rod material for comparisons.
For a 1-inch diameter rod, 4140 should almost give a thru hardness; 4130 about halfway(ref ASM Hdbk Vol 1), but I would rate toughness more important that strength. A failure would probably be due to a fatigue crack nucleating at the surface from maybe a thread root or a corrosion pit. In theory the lower carbon steels are tougher because they contain fewer brittle carbides. Whichever you pick, go for toughness.
RE: 4130 and 4140 comparison
As the other posters have implied, the only reason to use 4130 instead of 4140 is if there is fusion welding required. If no welding is required and your tie rod is more than about 1/2 inch in diameter, use 4140. There's no real cost difference, and 4140 will give at least 30 percent higher tensile properties in a normalized condition, while still having good elongation properties.
Regards,
Terry
RE: 4130 and 4140 comparison
RE: 4130 and 4140 comparison
RE: 4130 and 4140 comparison
- Direct bending from side loads ( drive over large rock and tie rod is asked to support weight of vehicle for a moment)?
- Bending from buckling when the tires try to auto-steer in response to whacking things, or when tires are jammed against rocks and the drive must exert maximum effort to the steering wheel?
- breaking after many hours of service?
I'd say upgraded materials would only be useful for maybe doubling resistance to 2 of the failure modes, and might even limit the options for trail repairs, whereas improved geometry of a basic material would offer immensely improved resistance to all three.
Dan T
RE: 4130 and 4140 comparison
Please don't take this as a personal attack; but -
Lesson for everyone, the OP's customer wanted a specific material, the OP recommended another for reasons not specified, my guess the recommended was "on-hand", but when the OP made the recommendation, he did not know what the differences were.
When your supplier/vendor makes an alternate material/process change, know what the differences are!
RE: 4130 and 4140 comparison
RE: 4130 and 4140 comparison