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panel steel?


mark105

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i work at a laser cutting place where we cut all kinds of steel shit now what im wondering is if i can use any of the shit we stock as panel steel for my car? this is where im confused, you say panel steel but shit im used to is all either mild steel in hot rolled or cold rolled and in various grades. so if any one can tell me what panel steel is would be sweet.

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Panel steel is typically pretty soft stuff so that it can be easily formed (malleable) with little springback.

Depends what you want though... if you're just doing little patchwork repairs and basic shaping pretty much any annealed, mild steel will work well. If you're looking at forming bigger sections you may want to look at either a deep drawing steel or a low-carbon mild steel as the forming will be easier.

Be very careful if you're forming bigger curved sections in cold-rolled low-carbon steel as you'll end up with the steel forming Luders Bands (ripples) via strain-aging after a period of time there a perfectly formed, painted panel will self-ripple over time. This can be avoided by using VERY low carbon/nitrogen steels (<0.003%), or by artificially over-aging the steel as part of the annealing process to try and encourage the formation of carbides in the steel to draw out the interstitial carbon that causes the strain-aging.

It's also possible to reduce this effect by performing a small-reduction cold-rolling pass (0.7%-1.9%) reduction after annealing. This introduces mobile dislocations that will allow a more continuous yield.

This should only really be relevant if you're doing large-scale deformation though such as complex curvatures in metal, which is a pretty advanced panelmaking skill.

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refrigerator and washing machine/drier bodys, roofs of old ladas, whatever you can find at the dump :rolleyes:

yeah probably better to do what those other guys said.

Nothing like recycling. Panel steel from other cars and appliances is generally good as it's aged steel, which typically will form pretty well :)

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nah need a bit more then a bonnet aye phil, asked dudes at work also they reakon just a bit of electro galv plus just gonna get it cut up at work also, can fuck round with tin snips but when it costs fuck all to get it lasered up might as well.

yeh spence will have to grab some that shit, got me a sweet mig too.

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sheet steel for cars, panel steel is thick as like 2mm + as far as im aware... mild steel for cars... i guess depends where and what you are patching up as old cars often use lead and brass as well ... keep in mind when you weld to differnt metals together the softer one will always rust out faster (galvanic/ electrolytic corrosion) and welding causes corrsion also (hydrogen embrittlement) which is usualy prevented with a interweld primer

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sheet steel for cars, panel steel is thick as like 2mm + as far as im aware... mild steel for cars... i guess depends where and what you are patching up as old cars often use lead and brass as well ... keep in mind when you weld to differnt metals together the softer one will always rust out faster (galvanic/ electrolytic corrosion) and welding causes corrsion also (hydrogen embrittlement) which is usualy prevented with a interweld primer

Panel steel is nowhere NEAR 2mm thick. Even heavy duty panels like you'd find on utes is typically only 0.9mm or so thick. 2mm steel is typically only used on car panels for welded reinforcements and attachment brackets etc. Lead and Brass is typically only used for seam-filling.

As for galvanic corrosion, it's got NOTHING to do with how hard/soft they are, it's about where they rank in the galvanic series (see here http://www.corrosionsource.com/handbook/galv_series.htm). Stainless steel is a very noble steel and is pretty soft compared to carbon steel, yet carbon steel will corrode much more readily.

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whenever i buy steel for work i ask the steel guys for sheet steel (perhaps a trade term) as for the technical corrosion mumbo jumbo i aced my corrision test at painting school and this is exactly what we were taught we didnt go into metal structure its self that much but we were taught how to identify corrosion and from what i was taught galvanic/electrolytic corrosion is when 2 un similar metals are in contact with an electrolyte(salty water, humidity ect that lets a current pass through) the softer metal will corrode much faster,.. makes sense to me after stripping my car back to bare metal i could find a reason for every piece of rust i found and a lot of it was where bolts are, and where other metal meet ... as for lead being used only for seam filling, in my car brass is used to spot weld sections of the car together and 50% of both of my rear pillars are lead .... the government curriculum must be lying to me :P im so getting my money back

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You're correct, galvanic corrosion occurs when two dissimilar metals are in contact with eachother in the presence of oxygen and an electrolyte. While it may be a rule of thumb that (automotively) softer metals are typically higher in the galvanic series, it's not entirely true and the mechanism for galvanic corrosion has nothing to do with the hardness of the material. Copper and Lead are EXTREMELY corrosion resistant (lead is often used unpainted on house roofs and doesn't corrode even after decades in the weather) compared to steel, yet is much much softer

It's strange that you say brass is used in spot-welding. Typically, spot-welds are a pure-fusion weld meaning that the only molten metal in the weld-pool is that of the two parent metals being joined. You're sure that a brass (or more likely bronze) filler-run hasn't been used on the spot-welds as a cosmetic finisher as is common automotive procedure. Brazing (molten bronze) is often used on older cars as a semi-structural and cosmetic inert filler.

Leadlining is extremely common in older cars for filling seams and other panelling imperfections (particularly in heavily curved areas). In an age before polymeric bodyfillers lead made an effective and easily workable filler. Of course these days, panel-pressing techniques are such that skim-filling on panels is no longer required.

As for the government curriculum..... don't necessarily believe everything they tell you. Hell they'll teach you that anthropogenic global warming's fact when, in reality it's anything but ;)

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(lead is often used unpainted on house roofs and doesn't corrode even after decades in the weather) compared to steel, yet is much much softer

lead isnt a ferrous metal hence it dosnt rust

spot weld another trade term im guessing my description being when there is a spot of weld apposed to a seam weld where it is joined all the way along.. and by brass or what ever i said i mean oxyacetylene welding (the gold looking shit)

my tutors were fucking awesome and one particularly knowledgeable about rust as he loved his old cars and has done many restoration projects that i was particularly interested in and pushed me towards doing the same with my car. its just all the theory we were taught was in lamens terms as most of my class was under 17 and its a more hands on subject...

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