What is the effect of increasing Al in steels?
What is the effect of increasing Al in steels?
(OP)
Can someone explain what is the effect of Al addition to steel. Of course I know that Al is added as a deoxidiser but I woulkd like to know specifically with respect to grain size and also in that case can someone explain why the restriction on Al in pipeline steels especially?
Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668





RE: What is the effect of increasing Al in steels?
When it comes to forming the pipe the inclusions then act as both stress raisers and cracks. This gives problems with during rolling with the formation of cavities (read as cracks) around the particles, cracking during welding welding, etc. On top of this the cavities that form around the inclusions can give rise to the formation of hydrogen cracking.
All in all, for pipeline applications it is best to keep the amount of Al as low as possible.
RE: What is the effect of increasing Al in steels?
typical properties for a Aluminium Killed Drawing Quality steel (2" gauge length) are:
Yeild strength: 25-32ksi
Tensile strength: 40-60 ksi
Elongation%: 42%+
R-value: 2.0+
N-value: .20+
I'm not familar with the pipe making industry so I'm not shure of the non-metallic inclusions problems related with aluminium killed steels. In the steel stamping industry you wnat a small amount of aluminium IE: .02-.06wt%, that way you know that the steel was properly killed.
Nikc
RE: What is the effect of increasing Al in steels?
Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
RE: What is the effect of increasing Al in steels?
However, the strength benfits of the reduced grain size are offset by the lower fracture properties. In pipeline steel you want achieve smaller grain sizes from the use of other mechnisms, e.g. precipitation hardening in micro alloyed steels or from controlled cooling.
Of course these advanced manufacturing methods make the pipeline steel more expensive.