ELONGATION PROBLEMS IN STEELS
ELONGATION PROBLEMS IN STEELS
(OP)
Despite chemistry being OK, we experience poor elongation in our plain carbon steels and low alloy steel castings (stainless is OK).
IE. 4140 normalized 4% - 5% annealed 8% - 10%
Can get higher elongations, but on the expense of Tensile and Yield strengths.
Melting - coreless induction furnace. Steel is deoxidized by ladle addition of .02% Al and .05%Ti.
Thank you
Mark
IE. 4140 normalized 4% - 5% annealed 8% - 10%
Can get higher elongations, but on the expense of Tensile and Yield strengths.
Melting - coreless induction furnace. Steel is deoxidized by ladle addition of .02% Al and .05%Ti.
Thank you
Mark





RE: ELONGATION PROBLEMS IN STEELS
Any hot working between casting and heat treatment?
Current elongation seems low to me.
RE: ELONGATION PROBLEMS IN STEELS
What is the section thickness of the casting. Is the test bar prepared from a keel block or removed from the casting. If it is later,check for microporosities and other inhomogenities.
Finally I hope the test bar preparation is satisfactory.
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: ELONGATION PROBLEMS IN STEELS
The strength levels vary from batch to batch.
YS 70 - 90KSI TS 120-140 KSI
There's no preliminary processing before casting.
The charge is made up of foundry returns, steel scrap, purchased certified ingots and ferro alloys for chemistry adjustment.
Test bar is prepared from the keel block. Section thickness average from .5" to 3". P and S levels less than .015, Al .005%.
We did some trial with Vanadium to refine grain size hoping to improve toughness - no success. And other than Ti for deoxidation and to fix Nitrogen, no other refiners are used.
Ps. In the past we used Al as a final deoxidizer (.1% ladle addition). For a couple years now, that's been changed to .02%Al and .05%Ti. As a result CO and N related defects has been greatly reduced and filter blockage was also reduced. (Probably less Al2O3 to clogged filter pores). Maximum flow, before filter blockage almost doubled!
Thanks
Mark
RE: ELONGATION PROBLEMS IN STEELS
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: ELONGATION PROBLEMS IN STEELS
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: ELONGATION PROBLEMS IN STEELS
Regarding FeSiZr and CaSi, what rate of addition should I use?
Also, should I use these alloys together, or separately?
And finally, what granulation should I request upon ordering these alloys?
Mark
RE: ELONGATION PROBLEMS IN STEELS
Test bar is removed (cut) using cut off saw, and no stress relived treatment is applied neither before or after cutting.
RE: ELONGATION PROBLEMS IN STEELS
RE: ELONGATION PROBLEMS IN STEELS
RE: ELONGATION PROBLEMS IN STEELS
We do deoxidize melt with Si. FeSi is added to the furnace shortly before tapping out, as a final Si chemistry adjustment, than Al and Ti is added to the tap stream into the ladle.
TVP - your suggestion adding .2% Al is probably to much.
May end up with final Al to high leading to further embrittlement, and also to much aluminium nitride precipitation causing "rock candy" type cracking when we quench and temper.
Thanks
Mark
RE: ELONGATION PROBLEMS IN STEELS
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: ELONGATION PROBLEMS IN STEELS
We pour variety of parts in this alloy, ranging from 1 lb to 600 lb. Temperature range: from 2800F to 3000F depending on casting modulus. Regardless of alloy, we try to pour at the lowest temperature that will provide soundness.
Mark
RE: ELONGATION PROBLEMS IN STEELS
_____________________________________
"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr
RE: ELONGATION PROBLEMS IN STEELS
You sharing of specific knowledge is extremely valuable and generous. I look forward to coming to India some day to meet you.
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: ELONGATION PROBLEMS IN STEELS
RE: ELONGATION PROBLEMS IN STEELS
And I must disagree, 1540 C - 1640 C are typical pouring temperatures for plain carbon or low alloy steel castings ie. 1030 or 4130. High alloy steels castings ie. 310 or 316 generally are poured cooler.
Mark