Parts to be hardened by case hardening process are made from a steel with a carbon content of 0.15% so that they will not respond to direct hardening.
The steel is subjected to treatment in which the carbon content of the surface layer is increased to about 0.9%.
When the carburised steel is heated and quenched, only the surface layer will respond, and the core will remain soft and tough as required.
12) The external surface of the part made of mild steel can be hardened by
Answer is:
Case hardening
Explanation:
Related Heat Treatment MCQ with Answers
Answer is:
500 Degree Centigrade to 560 Degree Centigrade
Explanation:
Gas nitriding process consists of heating the parts at 500°C in a constant circulation of ammonia gas for up to 100 hours
The completely stress-relieved workpieces are preheated (about 400°C) before being put in the salt bath (about 520-570°C).
Answer is:
Pyrometer
Explanation:
Pyrometer is used for measuring relatively high temperatures, such as are encountered in furnaces. Most pyrometers work by measuring radiation from the body whose temperature is to be measured. Radiation devices have the advantage of not having to touch the material being measured.
Answer is:
Induction hardening
Explanation:
Induction hardening is a method of surface-hardening in which the part to be surface-hardened is placed within an inductor coil through which a high frequency current is passed.
Induction hardening is a process used for the surface hardening of steel and other alloy components. The parts to be heat treated are placed inside a water cooled copper coil and then heated above their transformation temperature by applying an alternating current to the coil.