Price difference between Impact tested steel and non tested steel 3

It largely depends on the quantity that you are buying.
If you want a small amount of steel tested it will add a noticeable amount.
If you are buying a large amount then there will likely be no difference.

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P.E. Metallurgy, consulting work welcomed

Tony, it depends on your use. What industry, and what product are you making?

If you buy from a quality distributor for normal ASME, say a 2'x2' plates from 100 (40' x 8') heat, it will almost all be tested for impact - they just don't report it on the MTR. Ask for it.

If you are buying lower grade materials, say cheap W44, or consumer type materials, you can get the impact done yourself, impact/heat is around $300 CAD. They probably won't have mill results as normal.

Thanks guys! we will use A36 steel for the outer roof a LNG storage tank.
while API 620 doesn't require impact test for Minimum Design Metal Temperature above -20deg C (which is our case) client is requesting impact test

Like all the other answers, it depends. To perform the impact testing is not that expensive, for normal temperatures. Testing stainless at -321F is going to me move expensive than a -50F LCC requirement. It has been 10+ years since I sent any to an outside lab but it was about $150 at the time. That cost is insignificant when it represents 10 tons of castings, but really significant for a single 3 pound part.

However, if the impact requires a change to the standard process for that material, the cost will go up. ASTM A216 grade WCC is a plain carbon steel 70/40 tensile/yield with no impact testing. ASTM A352 grade LCC is a plain carbon steel 70/40 tensile/yield, with -50°F impacts. We would pour both parts on the same heat of steel. The WCC is normalized while the LCC is quench and tempered. This added heat treat requirement increases the cost. Adding a test also increases the possibility of the test failing and the material not being able to be used. Adding impacts also affects the weld procedure used for any repairs.

Bob

If the steel has declared/guaranteed impact properties, impact testing is mandatory whether you request it or not.

The A36 plate for the roof will no doubt be produced from coiled material. One assumes that the client requires impact testing at -20F per A-20. Your costs will be negligible.