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What is Marquenching?

What is Marquenching?

Marquenching/Martempering is a form of heat treatment applied as an interrupted quench of steels typically in a molten salt bath at a temperature right above the martensite start temperature. The purpose is to delay the cooling for a length of time to equalise the temperature throughout the piece.

Why is austempered steel better than tempered steel?

Although the austempered steel had slightly higher tensile strength, it had similar modulus, YS, and strain-hardening constants. Even with its higher tensile strength, the austempered steel had significantly higher tensile ductility at both room and low temperatures.

Does water quenching harden steel?

Water quenching is probably the oldest heat treatment process used by man to harden steel. It can be described as the rapid cooling of metal from the solution treating temperature, usually in the range of 845 o C to 870 o C for steels.

What are the limitations of Martempering?

Martempering is a method by which the stresses and strains generated during the quenching of a steel component can be controlled. In Martempering steel is heated to above the critical range to make it all austenite. The drawback of this process is that the large section cannot be heat treated by this process.

What is the difference between tempering and Martempering?

Various heat treatment processes are used to achieve the optimal hardness, strength levels and other features for particular applications. Tempering is the process of actually applying heat to the material in order to improve its hardness and other features. …

What are the limitations of martempering?

Why are bigger sections not used in Austempering?

Explanation: Big sections cannot be used for austempering as they cannot be cooled rapidly to avoid the formation of pearlite. As a result, only small sections up to 9 mm thickness are suitable for this operation.

Why do they dip hot metal in oil?

The vapors created by the searing hot metals act as an insulator that resists cooling. The metals do not reach the convection phase until the oil reaches 450 degrees or more. Metal treated in this way cool rapidly and evenly. This reduces the risks of cracking, distortions, and uneven soft spots.