hrvatski

Effects of concentration watermiscible metalworking fluids on cooling rate

Quenching is the most common operation of metal heat treatment, which involves adequate cooling from given austenite temperature to achieve fully transformation into martenzite structure. The cooling rate of quenching media mainly depends on thermal characteristics of the metals, section thickness of the workpieces, and the quenching medium heat-removal properties. Correct selection of adequate cooling media decreases risk of tension formation, eventual cracking, and workpieces distorsions. The most commonly used cooling media for quenching steel are water, vegetable and mineral oils, polymer solutions, molten salts, fluidized beds, gasses, and air. Water is a severe quenchant till oils cool more slowly than water but their main disadvantage is high fire hazard. Using watermiscible fluids combines positive properties of those two types of quenchant media, the water and the oils. In this work are presented physical and chemical properties of watermiscible metalworking fluids as cooling media. We prepared several fluid mixtures with water in different concentrations. For every concentration of test cooling fluids are plotted cooling curves, determined cooling rates and H-values using ISO 9950 standard.

metal heat treatment; hardening; quenchants; watermiscible quenchant fluids

nije evidentirano

engleski

Effects of concentration watermiscible metalworking fluids on cooling rate

Quenching is the most common operation of metal heat treatment, which involves adequate cooling from given austenite temperature to achieve fully transformation into martenzite structure. The cooling rate of quenching media mainly depends on thermal characteristics of the metals, section thickness of the workpieces, and the quenching medium heat-removal properties. Correct selection of adequate cooling media decreases risk of tension formation, eventual cracking, and workpieces distorsions. The most commonly used cooling media for quenching steel are water, vegetable and mineral oils, polymer solutions, molten salts, fluidized beds, gasses, and air. Water is a severe quenchant till oils cool more slowly than water but their main disadvantage is high fire hazard. Using watermiscible fluids combines positive properties of those two types of quenchant media, the water and the oils. In this work are presented physical and chemical properties of watermiscible metalworking fluids as cooling media. We prepared several fluid mixtures with water in different concentrations. For every concentration of test cooling fluids are plotted cooling curves, determined cooling rates and H-values using ISO 9950 standard.

metal heat treatment; hardening; quenchants; watermiscible quenchant fluids

nije evidentirano