Structural variations in heat treated low alloy steel forgings

A comparison has been made between the dynamic and static tensile yield strengths of eight steels varying from mild steel to a heat-treated low-alloy steel, the rate of loading in the dynamic tests being such as would occur in a ship under the action of an underwater explosion. The dynamic yield strength of the steels with low static strength was 20–30 per cent greater than their static yield strength but, for the stronger steels, the increase was less, being negligible in the case of the heat-treated low-alloy steel. This result conforms with the findings of other investigators, and shows that any increase in strength under the dynamic loading considered is too small to be of importance in design.

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Carbide composition changes in a low alloy steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135708 ◽

1990 ◽

Vol 48 (2) ◽

pp. 420-421

Author(s):

Z. Larouk ◽

R. Pilkington

Keyword(s):

Alloy Steel ◽

Prior Austenite ◽

Creep Behaviour ◽

Low Alloy Steel ◽

Austenite Grain Size ◽

Austenite Grain ◽

Heat Treated ◽

Prior Austenite Grain Size ◽

Composition Changes ◽

Prior Austenite Grain

Durehete 1055 is a 1%Cr1%Mo¾%V low alloy steel used as bolting material at 565°C. It also contains 0.08%Ti and 0.005%B to improve the creep behaviour, but deleterious properties have been reported, due to the presence of trace elements such as P and Sn. The present work has been an attempt to understand this problem by examining three vacuum melted casts of this steel containing selected additions (wt.%) of 1) 0.08 Ti, 2) 0.08 Ti and 0.02 P; and 3) 0.08 Ti and 0.02 Sn. The material was heat treated for 2h at 980°C, W.Q., and tempered 4h at 680°C, giving a prior austenite grain size of 8 μm. Specimens were then crept for various times at 565°C. After test, metallographic samples were prepared from both the gauge lengths (stressed) and heads (unstressed) to enable the production of carbon extraction replicas. These replicas were examined in a Philips 400T electron microscope, and carbides analysed using EDS.

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