Quench System Design

Agitation is one of the most critical areas of quench system design. This article provides an overview of the impact of agitation on quench uniformity, followed by a general discussion of the selection and use of various types of agitators, including recirculation pumps, jet mixers, forced air (sparging), and impellers. A brief overview of heat-exchanger types and their selection criteria is also provided, along with simplified calculations for approximating heat-exchange requirements. The methods of selecting a quenchant are provided. Recommendations for system maintenance are also described. Much effort is placed on the proper design of the furnace for temperature and atmosphere uniformity, proper temperature control, and exact carbon potential. However, the design of the quench tank can have a drastic effect on the overall system performance, with proper design ensuring proper mechanical properties (hardness, strength, and fracture toughness) as well as distortion control.