High Hot Hardness Research Articles

CARPENTER V.S.M.

Abstract Carpenter V.S.M. is a molybdenum, chromium steel which offers good resistance to heat checking, provides high hot hardness and good resistance to wear and abrasion at elevated temperatures. It is recommended for valve and bearing components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-179. Producer or source: Carpenter.

CALMAX

Abstract CHB CALMAX is a chromium-tungsten-cobalt hot work steel recommended for the most severe applications. It has an extremely high hot hardness combined with a great toughness at high temperatures. This datasheet provides information on composition and hardness. It also includes information on forming, heat treating, and machining. Filing Code: TS-177. Producer or source: Uddeholm Aktiebolag.

VASCO SUPREME

Abstract VASCO SUPREME is a high carbon, cobalt type of high-speed steel combining very high hardness, hot-hardness, wear resistance and toughness. It possesses performance qualities surpassing those of commonly used grades of high-speed steel. This datasheet provides information on composition and hardness as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-4. Producer or source: Vanadium Alloys Steel Company. Originally published January 1953, revised May 1962.

Tungsten-Columbium-Tantalum Alloys

Alloy compositions blanketing the tungsten-columbium-tantalum ternary system were screened by means of hardness tests at 2300° to 2900°F and weight gain in oxygen at 2190°F. These tests delineated areas combining high hot-hardness with at least tenfold improvement in oxidation resistance over that of pure metals.

Temperature dependence of the hardness of secondary phases common in turbine bucket alloys

Representative examples of the most common types of secondary phases in turbine bucket alloys have been synthesized in bulk and their hardness measured from room temperature to 800°C. It is concluded that high hot hardness of the dispersed phase is an important factor in the high temperature strength of alloys but that other (as yet not explicitly identified) factors are also significant.

Exhaust Valve Life: Some Metallurgical and Mechanical Considerations

The factors controlling heat flow into and from the head of an exhaust valve are discussed for the purpose of indicating the means by which temperature, the overriding important factor in exhaust valve failure, can be reduced. This analysis suggests the lines along which the designer and the metallurgist must co-operate. The causes of exhaust valve failure are reviewed, and the conclusion is reached that the majority of these are the result of corrosion fatigue. Even for resistance to burning the two properties inherent in resistance to corrosion fatigue, namely resistance to corrosion and good hot strength, are essential. Laboratory tests for determining resistance to high temperature corrosion fatigue and hot hardness are described, and some results given for exhaust valve materials. Corrosion fatigue resistance is considered to be so significant a factor in exhaust valve failure that it is suggested that laboratory tests to determine this property should form the basis for the development of improved exhaust valve alloys.