Quartet Thermal Engineering Pvt. Ltd. Manufactures Heat Treatment Continuous Austempering Plants Quartet Thermal Engineering Pvt. Ltd. Supplies wide range of Heat Treatment Plants and Furnaces. The Heat Treatment Continuous Austempering Plants are widely used for meeting the demands of aus-tempering applications of various metals. This process helps in providing a tough, high-strength component that resists embrittlement. The Heat Treatment Continuous Austempering Plants are very efficient and also demands very low maintenance.