How do AISI 1045 properties compare with those of A668? 1

[springhanger]

How do AISI 1045 properties compare with those of A668? If someone was to use AISI 1045 to make forged steel items, how would the properties compare with forgings made of A668?

 

[kenvlach]

No valid comparison.
ASTM A668 is a performance/quality standard for forgings in various heat treat conditions, while AISI 1045 is merely a composition. Generally, a composition typically used for the X2 grade in A668 is within 1045 limits, but 1045 in any particular heat treat condition may fail to meet the corresponding A668 mechanical property requirements (such as %elongation).

Table X2.1 in A668 gives carbon steel compositions typically used (those found to help meet the property requirements):
For Grade X2 (closest to 1045), typical limits are 0.45% C, 0.90 Mn, 0.04 P, 0.04 S and 0.35 Si. All < 1045 limits; while 1045 doesn't specify Si, plain carbon steel per AISI definition may contain 0.60% Si as well as 0.60% Cu. So, to meet the performance requirements of A668, stricter composition limits seem necessary.

See A668/A668M-04 Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use

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