Quenched and Tempered Steels

Most hydrocracker reactor shells (U.S. and European) have been fabricated from normalized 

Recent British work on 2-1/4-Cr 1-Mo Q T steel has indicated lower values of rupture strength than those listed in the Metal Properties Council report, possibly because a relatively high tempering temperature was used. These properties are such that for a BS 1515 vessel the design stress at 800°F would be based on rupture strength. 

The British have also shown the need to limit the tempering time to achieve optimum rupture 

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Tabic 3.9. Comparison of Mild and Low-Alloy Quenched and Tempered Steels (111... 

The rotary drill bits are generally made from quench and tempered steel alloys such as AISI 3115 to 3120, 4620, 4815 to 4820 and 8620 to 8720. The only corrosion related problem that can arise may result from a hydrogen sulfide environment. The bearing in the roller rock bits can be damaged by H S contamination of drilling fluid. However, a well conditioned drilling fluid at... 

Fig. 8.12 Effect of applied stress intensity upon crack velocity for high-strength (180 GN/m UTS) quenched and tempered steel (AFC 77) in distilled water (after Spicdel )...

EN 10083-1, Quenched and tempered steels — Part 1 Technical delivery conditlonsfor special steels. 

P.P. Puzak, "Explosion-Bulge-Test Performance of Low-Carbon Ni-Cr-Mo-B Quenched and Tempered Steel Weldments ,... 

As mentioned in Sec. 9-, the breadth of an x-ray line often correlates well with the hardness of the specimen. Marburger and Koistinen [16.30] also showed that the hardness of certain quenched and tempered steels is related to the breadth... 

P. Konkol, Characterization of Friction Stir Weldments in 500 Brinell Hardness Quenched and Tempered Steel, Proceedings of the Fourth International Conference on Friction Stir Welding, May 14-16, 2003 (Park City, UT), TWI, paper on CD... 

Reference 2 reported on welds in 0.29C-Mn-Si-Mo-B quenched and tempered steel using a PCBN tool. Weld thicknesses included both 6.4 and 12.7 mm. Microhardness of the stir zone was found to approximately equal that of the base metal. Significant softening was observed in the HAZ. Transverse tensile properties of... 

Another convenient conversion is that of Brinell hardness to ultimate tensile strength. For quenched and tempered steel, the tensile strength (psi) is about 500 times the Brinell hardness number (provided the strength is not over 200,000 psi). 

K scc depends on metallurgical factors (it usually decreases as the strength of the steel increases, even though it also depends on the microstructure of the material, e. g. it is lower in quenched and tempered steel than in cold-worked steels) and on environmental factors (for instance, in alkaline environments and in the absence of chlorides, Kfscc so high that normal mechanical failure takes place before stress corrosion cracks can develop). 

The approximate tensile strength in PSI can be ascertained by multiplying the BrineU hardness number x 500. For metric applications the tensile strength in N/mm can be obtained by multiplying the BrineU number by 3.54 for annealed steels, and 3.24 for quench and tempered steels. 

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