Has anyone done this successfully, and had it on a car for some time to see if there is any failure? My thought is if you heat it up and bend it to the desired location, then reheat the material above its critical temperature (I am assuming 4130 or 4340 steel was used) and then quench the material, I should have its stiffness close to where I started with. Any metallurgy guys out there???
I'm sure it can be done by heating with a torch, bending it and locally tempering the area. But will it break later, maybe, maybe not. 4130 can be hot-worked at around 1500-2000 F. Both 4130 and 4340 are high tension alloys and should only be heat treated uniformly. The right way is to do a full furnace anneal before bending, the temperature is around 1550-1600 F. It should be oven-cooled @ 50F/hour down to 600F-900F (depending on the alloy) and then air cooled. After bending, do a standard heat treat at around 1525F-1600F (again, depends on the alloy), oil quenched, followed by a tempering to the desired ksi properties. I go with standard charts for a specific alloy that I want to work on. The $64K question is, do you know exactly what alloy sway bar you have? Bob
heating and letting it cool by itself doesn't change anything. spring shops heat leaves and roll eyes in the end, and they don't break.
As I was the foreman for a company that manufactures sway bars, they were never heated for bending purposes. They were bent in computer controlled bending machines. Only the ends were heated so they can be progressively flattened then punched
Also let me not this. It will be bent as close to the spindle mount as possible. Which will not be in the torsional section of the bar. I dont have a machine capable of bending something that stiff. But perhaps I could find one and do a cold bend.
We bent mine cold on a 60,000 lb press and so far its ok My engineer buddy said it will be OK Many springs are made with tempered wire and not heat treated
Which makes sense. There is probably enough stiffness within the properties of the steel which may have been cold worked in. And heat treat is another process which always costs money. I would do the file trick on it to get a better idea of how hard it is. The trick is to find a big press somewhere. Bob
I just bent some 3/8" x 6" wide plate today in my wood splitter..........I will make a die and try bending it cold, hopefully it has enough pressure to do it. FYI, a wood splitter makes one heck of a good press, just a matter of making the right dies.
Report back if you can. all I can add about heating quenching of very, very small hardened springs, round wire type or flat...they always break. After reading this thread I will try cooling it naturally, not quench. Edit; these tiny spring parts are so brittle to begin with, that they also break if I try cold bending.
Rearching leaf spring steel is by press work and no heating to the spring steel. Rolling spring eyes is done by using a small furnace that heats the end of the spring leaf that has been cut at the correct angle and the correct length. After the spring leaf is heated and the eye is rolled, the new eye is heated some, and the spring leaf is layed off to the side to cool with ambient air temperature. Before I worked at the place I know this from, they tempered raw steel into spring leaves before you had places to order them from. Today, we have several sources. I'm the driveshaft guy and have learned some about springs from observations and experiences and sales. 23 years of them.
i have bent a sway bar with heat and it survived on the street, never let your car fall off a floor jack and land on the sway bar I also have a car with a cut and welded sway bar that looks to be 1 1/4 in thick it also seems to survive on the street
Been heating, bending then for years. No problem. Just allow the heated area to normalize by itself (no quenching in oil or water, no blasting with shop air etc.). Sway bars can also be cut and TIG welded ONE TIME/IN ONE SPOT sucessfully. The welded heat-affected area needs to be normalized but it can be done and I don't care what any of the "experts" here say. Many many successful modifications under our belt over a period of 20+ years.
Back in the "60's we would heat and bend and then quench with old motor oil. It was felt that air cooling would cause the bar to become annealed and then it would bend. Saw a few that did bend. But never knew for certain that they had been heated. Matt
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