Factors affectig the production and performance of thick section high chromium-molybdenum alloy iron castings
Massive high chromium-molybdenum alloy iron castings are now being produced in large tonnages for the mining industry, for use in large roller pulverizers, in heavy duty abrasion resistant pumps, and for many other applications demanding a combination of abrasion resistance and toughness unobtainable in other alloy irons. Systematic research, particularly over the past decade, on the interrelated parameters which can cause problems in the foundry or failures in service has played a significant part in the success of the high chromium irons in thick section castings. Data from this research are presented on the separate and combined effects of C, Ch, Mo, Ni, Cu, Mn, Si, Ti and Al on the hardenability, toughness and abrasion resistance of the high chromium irons in both the as-cast and heat treated conditions. Changes in production techniques have helped avoid foundry problems and wasteful use of alloys and energy. These changes are reflected in more consistent performance in service and reduced incidence of casting failures. Changes in composition which facilitate cryogenic transformation of retained austenite, or provide wider latitude in subcritical transformation of austenite, are discussed as these techniques may prove increasingly important as energy becomes more expensive. A summary is presented of the physical metallurgy of high chromium-molybdenum irons, with emphasis on the microstructures obtained in thick section castings, the influence of alloying elements on hardenability and the types of heat treatments available for controlling microstructure. The production and utilization of these irons in thick section castings, particularly the ways of avoiding problems in the foundry and of obtaining castings which provide more consistent performance and reduce incidence of catastrophic failure in service are discussed.
- OSTI ID:
- 5644429
- Report Number(s):
- NP-24344
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
ALUMINIUM
AUSTENITE
CARBON
CARBON ADDITIONS
CASTINGS
CHROMIUM
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
COPPER
CRYSTAL STRUCTURE
ELEMENTS
FABRICATION
HARDNESS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE
MARTENSITE
MECHANICAL PROPERTIES
MELTING
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
MINING
MOLYBDENUM
NICKEL
NONMETALS
PHASE TRANSFORMATIONS
PULVERIZERS
PUMPS
REFRACTORY METALS
RESIDUAL STRESSES
SEMIMETALS
SILICON
STEELS
STRESSES
TITANIUM
TRANSITION ELEMENTS