Search Results for quench tank design

Quenchant agitation can be obtained by circulating quenchant in a quench tank through pumps and impellers. The selection of the agitation method depends on the tank design, type and volume of the quenchant, part design, and the severity of quench required. This article describes flow measurement methods, temperature control, materials handling, and filtration processes during the agitation process. The maintenance of quenching installations is also discussed.

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.

Intensive quenching (IQ) is an alternative method of hardening steel parts. Two types of IQ methods are used in heat treating practice: IQ-2 and IQ-3. IQ-2 is implemented in IQ water tanks, which are usually used for batch quenching of steel parts. IQ-3 is conducted in single-part processing using high-velocity water flow IQ units. This article presents a detailed description of IQ technology, related equipment, and IQ applications. A review of intensive quench system design and processing is provided, including numerical design criteria, steel selection, quenchants, properties (especially optimal residual stress profiles). Several specific applications of intensive quenching are also provided.

The role of a mixer/agitator in quenching applications is to control the mixing environment in order to meet the process criteria. This article provides the basic fundamentals of the sizing of agitators, tank geometry importance, and other considerations for the application of agitators in quench tanks. It also discusses the differing methods for the sizing and selection of agitators for quench tank applications.

Molten salt, including nitrite/nitrate salts, is the quenching medium most commonly used in austempering and marquenching of ferrous materials. This article describes the use of molten salts in the quenching of ferrous materials. It provides information on the processing and operation of salt quenching including considerations of time, temperature, environment, and safety, as well as critical characteristics such as the composition of the quenchant, agitation, and water additions.

The fundamental objective of quenching is to preserve, as nearly as possible, a metastable solid solution formed at the solution heat treating temperature, by rapidly cooling to some lower temperature, usually near room temperature. This article provides an overview of the factors used to determine a suitable cooling rate and the appropriate quenching process to develop a suitable cooling rate. It discusses the three distinct stages of quenching: vapor stage, boiling stage, and convection stage. The article reviews the factors that affect the rate of cooling in production operations. It discusses the quenchants that are used in quenching aluminum alloys, namely, hot or cold water and polyalkylene glycol. The article also describes the racking practices for controlling distortion and the level of residual stresses induced during the quench.

Quenching severity is agitation-dependent and therefore, magnitude and turbulence of fluid flow around a part in the quench zone are critically important relative to the uniformity of heat transfer throughout the quenching process. This article provides an overview of the measurement principles for different types of flow devices used in production quench tanks, namely, vane sensors, fluid-quench sensors, caterpillar quench-evaluation sensors, and thermal probes. Various methods of flow measurement in commercial quench tanks may be acceptable for adequate control to ensure a high-quality production process.

Computational fluid dynamics (CFD) provides an efficient, alternate, virtual approach for simulating and analyzing quenching processes with an impact on component design, manufacturing process, and quality. This article provides domain insights for quenching researchers and CFD practitioners for the modeling of the industrial quenching process and for supporting the diverse multifunctional needs in an industry, ranging from primary metallurgical companies (steel, aluminum, and other alloys), original equipment manufacturers, engineering companies, captive and commercial heat treating facilities, quench system manufacturers, and quench fluid suppliers. It describes the governing differential equations for the fluid flow and heat-transfer phenomena during quenching. The article also discusses different modeling categories to determine a CFD methodology for quenching.

Quenching refers to the rapid cooling of metal from the solution treating temperature, typically between 465 and 565 deg C (870 and 1050 deg F) for aluminum alloys. This article provides an overview on the appropriate quenching process and factors used to determine suitable cooling rate. It describes the quench sensitivity and severity of alloys, quench mechanisms and the different types of quenchants used in immersion, spray, and fog quenching. The article provides a detailed description of the quench-factor analysis that mainly includes residual stress and distortion, which can be controlled by proper racking. It concludes with information on agitation and the quench tank system used in the quenching of aluminum alloys.

Intensive quenching (IQ) is an alternative method of hardening steel parts, providing extremely high cooling rates within the martensite-phase formation temperature range. This article begins with the description on the general correlation between steel mechanical properties and cooling rate during IQ. It presents a review of batch intensive quenching (IQ-2) methods and single-part intensive quenching (IQ-3) methods as well as practical applications of these methods. The article provides useful information on the effect of heat flow on cooling in these methods, and discusses the improvements achieved in part microstructure, mechanical properties, and stress conditions of steel, after intensive quenching. It also describes the reasons for part distortion in IQ, and reviews the types of quench systems used in IQ-2 and IQ-3 processes.

Flow visualization is an important characterization process to not only understand uniformity of the interfacial cooling mechanisms, but also to characterize the overall impact of agitation on the uniformity of the overall cooling process. This article focuses on thermal flow simulation and visualization in the quenching process. The study presents the effect of bubbling, boiling, and breaking the steam film on the heat-transfer coefficient during the agitated quenching process.

Induction heating has many different applications, such as melting, heating stock for forging, and heat treating. This article begins with a discussion on the types of power supplies, namely, solid-state power supplies and oscillator tubes. It provides information on system elements, including cooling systems, power supplies, heat stations, work handling fixtures, induction or work coils, and quench systems. The article discusses the influence of system elements on induction heat treating system design. It also deals with the general theory, types, and applications of induction coils.

In this article, an in-depth overview of petroleum quenching oils is provided, including oil composition, use, mechanism of the oil quenching processes, oil degradation, toxicology and safety, and quenching bath maintenance.

This article provides information on the various stages of quenching, sources of distortion, and factors that affect the creation of thermal gradients. It reviews the various determinations of heat-transfer coefficients by the thermal conductivity and diffusivity method, analytical and empirical methods, application of cooling curves, computational fluid dynamics, and the inverse conduction calculation and measurement of parts. Suitable examples are also provided.

Induction heating for hardening of steels has advantages from the standpoint of quenching because parts are individually processed in a controlled manner. This article provides information on the effect of agitation, temperature, hardening, residual stresses, and quenching media, on quenching. It also describes various quenching methods for steel induction heat treating, namely, spray quenching, immersion quenching, self or mass quenching, and forced air quenching. The article also reviews quench system design and quenchants and their maintenance.

This article presents the fundamentals of induction hardening (IH). It focuses on liquid quenching technology, but some specifics and brief comments are provided regarding alternative quenching media as well. The article provides a discussion on the following quench modes that can be applied in IH using liquid media: conventional immersion quenching, open spray quenching, flood quenching, and submerged quench or submerged spray quench. It also focuses on four primary methods of IH: scan hardening, progressive hardening, single-shot hardening, and static hardening.

The fluidized bed provides a means for exchanging heat between a metal part, the solid particles, and the fluidizing gas and which is viable for quenching. This article briefly considers the design aspects of the gas distributor, plenum, container, immersed cooling tubes and surface air spray cooling system in the quenching fluidized bed. It describes the fundamental factors affecting quenching power of the fluidized beds, namely, particle size, particle material, fluidizing gas composition, fluidizing gas flow rate, bed temperature and pressure, and the arrangement of quenched parts with respect to one another and to the bed. The article discusses the advantages, disadvantages, various applications and processes, including conventional batch quenching, two-step batch quenching, and continuous quenching of fluidized bed quenching, in detail.