An Effect of Pib Additives to Mineral Oil Resulting in Elimination of Film Boiling During Steel Parts Quenching

Abstract

To control the process of film boiling during quenching in oils, quench oil makers as a rule manipulate physical properties such as a surface tension and viscosity. However, there is much experimental data showing that special additives can eliminate film boiling in oils without changing their physical properties and which is counterintuitive. Authors explain such phenomenon by showing that the addition of a special additive, for example PIB (polyisobutylene polymer), will create an insulating layer on the surface of steel parts during quenching in oils that will eliminate film boiling without affecting physical properties of the oil. Insulating layer decreases initial heat flux density which becomes less than critical one and of the oil will not begin film boiling during quenching with the PIB additive. Authors believe that such approach will allow engineers to solve effectively the problem of part distortion after quenching. The new oil quenchant containing special additive PIB is patented in Ukraine and is manufactured by Barkor Ltd for needs of the heat treating industry.

Research on Maximizing Critical and Reducing Initial Heat Flux Densities to Eliminate Any Film Boiling and Minimize Distortion During Quenching

“…o C: 1 -no additives at all; 2-7 % of PIB 950; 3-5 % of PIB 1300; 4-4 % of PIB 2400 [13,14] As seen from Fig. 7, a small amount of PIB additives decrease completely film boiling during quenching due to creation of an insulating layer [13,14]. This is a new approach in controlling cooling intensity of liquid quenchants.…”

“…Also, special additives creating micro-insulating layer on the surface of steel parts are used to decrease initial heat flux density and by this way eliminate film boiling (Fig. 7) [13,14]. o C: 1 -no additives at all; 2-7 % of PIB 950; 3-5 % of PIB 1300; 4-4 % of PIB 2400 [13,14] As seen from Fig.…”