I'm not familiar with types 1 through 5. Are you referring to Grades 42, 50, 55, 60, and 65? The grades represent the ksi yield strength. Grades 42, 50, and 55 are intended for riveted, bolted, or welded structures. Grades 60 and 65 are intended for riveted or bolted construction of bridges, or for riveted, bolted, or welded construction in other applications.
Scott,
I wasn't familiar with the Types either until I actually read A572 front to back(zzzzzzzzzzzz). But its not the yield Grades, it has to do with specific alloy chemistry. Alloying will vary as to whether its making use of Vanadium, Columbium, Nitrogen, Titanium, or combinations thereof.
Type 1 Cb
Type 2 V
Type 3 Cb/V Cb+V
Type 4 V/N
Type 5 Ti/N/V
There has to be some history and metallurgical reasoning behind the requirement to report. This is what I'm looking for.
thanks
By CWI555 
Date 10-26-2007 18:53
Edited 10-26-2007 18:56
One possible vien to research,
I've worked a few contracts where A572 was brought into the states via a Kiev Ukraine mill (Kryvorizhstal). I payed them a visit at that facility and was told by their metallurgist that the steel of that grade produced in the region was known for higher levels of vandium and columbium (as documented in the mtr's on my project at the time). Russian standards during the cold war were different from the west in that they allowed higher levels of those two elements. Walking their mill felt like a step back into history. Severstal in Cherepovets Russia proper was exceptionally different.
Severstal has ungone many manifestations in the last 50 years, and was the pet project for the russian ministry of ferrous metallurgy. It recieved many upgrades that Kryvorizhstal did not.
I believe some historical research into these two sites may yield some influence on western standards.
I would like to know about this too.
As a start I dug up what I think is 'the' patent for Type 5 (Ti). This provides excellent background info on the alloy and the reasons behind the additions of Ti and V and the metallurgy involved. Patent # 5,326,527 1994.
If it ain't the patent for Type 5 it certainly explains Type 5.
