An intensive quenching (IQ) process is an environmentally friendly method of hardening steel parts. Digitally controlled, IQ employs highly agitated and directed water flow as the quenchant. An extremely high cooling rate applied uniformly over the entire part surface area induces high surface compressive stresses which prevents part distortion and cracking while forming a very fine microstructure. The fine microstructure results in better mechanical properties compared to properties imparted by conventional oil or polymer quenching. The improved mechanical properties enable engineers to design stronger steel parts for higher power density mechanical systems often using steels containing a less amount of alloying elements or using less expensive plain carbon steels. A broad and deep body of knowledge documents IQ’s ability to tailor a steel component’s microstructure to improve steel parts mechanical properties and performance. A sampling of data will be presented including surface and core hardness, tensile, yield and impact strength, elongation and reduction in area, residual surface compressive stresses for through hardened steels and the carburized grades. IQ systems can be readily “dropped in” to existing steel processing facilities or integrated into next generation heating and cooling systems through teamed relationships with equipment makers and part manufacturers seeking a sustainable future.

Intensive water quenching (IQ) is not a new technology. It goes back over 50 years in Russia and 18 years in the USA. The use of IQ after induction through-heating on “Limited Hardenability” Steels to eliminate the long carburization cycle for case hardened parts is one of many successful applications of IQ.

Water impinging jets have been widely used in quenching of hot steel plate. The role of staggered-array water jet on intensive quenching is experimentally investigated at fixed jet Reynolds number of 35,000 and nozzle-to-plate distance of 100 mm. The time-and space-resolved heat flux and heat transfer coefficient can be exactly measured with 5 different staggered-array jet configurations ranged from S / D = 3 to 8. The heat transfer characteristics were measured by a novel experimental technique that has a function of high-temperature heat flux gauge. The qualitative flow visualization showed complex flow patterns for staggered-array configuration, which exhibits a radial flow interaction issuing from adjacent water jets. The results show that the maximum area-averaged heat flux was observed at S / D = 3. This is caused by the radial interaction between adjacent jets which affects different boiling heat transfer on a hot steel plate. The maximum cooling rate at the surface reaches nearly 600°C/sec during water jet quenching. This study is motivated by the fact that a new design of intensive quench process requires the role of staggered-array water impinging jet on its heat transfer characteristics. In case of intensive quenching process for heat treatment, the water jet quenching is nominally started from above the austenitic temperature of 900°C to the finish quenching temperature of 300°C at which the martensite formation starts. Finally the current study is to provide quantitative local and average heat transfer characteristics of the staggered-array water jet quenching.