How to determine the Thickness tolerance of the Cold Rolled Steel

[R. Webb]

I am being asked to give the mills thickness tolerance for cold rolled steel - commercial quality by my customer. The steel supplier and the mill will not give a thickness tolerance. They will give a guideline, but no tolerance sheet, of the nominal dimension +0.0, -.0055. I am not sure how to respond to my customer. I have always assumed the customer gives the tolerance and if it is too tight you request relief -- am I wrong?

 

[PaulJSmith]

Re: Sheet Metal Thickness

There is a good deal of allowance in the sheet metal industry, and most suppliers will be every bit as hesitant to give you solid tolerances as your current supplier. I have seen some tolerances that overlap the nominal of the next gauge. Here's one example I've found: http://www.coyotesteel.com/resources_toleranceranges.shtml

I think your best bet is to ask your customer what they require, then find a supplier willing to hold that tolerance.

 

[Golfman25]

Re: How to determine the Thickness tolerance of the Cold Rolled Steel ?

Welcome to the steel industry, where almost anything goes.

If you are using "sheet" product, you generally will not get a tolerance. Just a gage - 12, 16, etc.

If you need a tolerance, you're looking at a "strip" product. You will be looking at something between +/- .002 to .005. Expect to pay more.

As Paul stated, figure out what tolerance you need. Then work with your supplier to achieve that result. Good luck.

 

[normzone]

Re: How to determine the Thickness tolerance of the Cold Rolled Steel ?

I've been down this road before. I spoke with my supplier, who told me what the posters above have said. I no longer have that data, but if you speak nicely with them usually somebody will provide you with some data or a link to same.

They said that for customers that have fussy tolerancing they can pick and choose from lots, but it will affect availability and pricing.

 

[R. Webb]

Re: How to determine the Thickness tolerance of the Cold Rolled Steel ?

I am not sure what the customer wants as they are asking me to get the mill tolerance rather than telling me what tolerance they want. I have found a few tolerance charts and, as expected, they do not agree. Without direction from them I will choose the most reasonable standard with the widest tolerance and use that. AISI Chart seems to work for what I normally see from commercial quality steel. If anyone is interested I found this link,

http://spectraresources.com/pdf/carbonSteelSheets_gaugeChart.pdf


Thanks for your comments - much appreciated

 

[Darrell B]

Re: How to determine the Thickness tolerance of the Cold Rolled Steel ?

It will vary from mill to mill. Good luck- I have been working with structural shapes for many years, and dimensionally it's like the wild west.

 

[Big Jim]

Re: How to determine the Thickness tolerance of the Cold Rolled Steel ?

I am not sure what the customer wants as they are asking me to get the mill tolerance rather than telling me what tolerance they want. I have found a few tolerance charts and, as expected, they do not agree. Without direction from them I will choose the most reasonable standard with the widest tolerance and use that. AISI Chart seems to work for what I normally see from commercial quality steel. If anyone is interested I found this link,

http://spectraresources.com/pdf/carbonSteelSheets_gaugeChart.pdf


Thanks for your comments - much appreciated

May I suggest that you go back to your customer and tell them what you have learned, then ask if that is enough or if they need more information. If they need more, tell them that you want to help, but it would help you if they tell you more of what they need to know and why they need to know it. When armed with fuller detail of what they want you may be able to help them get where they want to go.