heat treatment furnaces classification
Bell type furnace
A periodic heat treatment furnace in which the heated material is heated in a hood. It is mainly used for annealing thin sheet stacking or steel coil. The bell furnace usually consists of an outer cover, an inner cover and a hearth. The heated object is placed in the inner cover (muffle cover) to provide heat between the inner cover and the outer cover. Generally, a controlled atmosphere is introduced into the inner cover. After the heating, heat preservation and slow cooling process is completed, the outer cover is hoisted, and the stack or coil is cooled in the inner cover; after cooling to a given temperature, the inner cover is removed, and the plate or coil is cooled in the air, and then discharged. Fig. 1 is a bell annealing furnace for sheet stacking. The burner is installed on the hearth. There are two types of bell furnace for cold rolled coils: single stack furnace and multi stack furnace. The multi stack furnace can place 2 to 8 stacks of coils on a rectangular hearth, and each stack is buckled with a separate circular inner cover. A circulating fan is installed at the lower part of the inner cover to strengthen the control of atmosphere and promote convective heat transfer between steel coils.
Bell type furnace
Heat treatment material is transported by roller in furnace, and a roller is installed every certain distance along the whole length of furnace. The material runs on the roller, and burners can be arranged to heat the furnace above and below the roller (Figure 2). There are two kinds of rollers, ring roll (with disc roll ring) and flat roll. The former can only be used for heating plate, section steel, pipe and bar. The outer roll sleeve of rollers is usually made of heat-resistant steel, and some of them are made of silicon carbide. High temperature furnaces (1000-1150 C) adopt water-cooled shaft and heat-resistant steel furnace rollers with adiabatic lining, or full water-cooled furnace rollers. In order to prevent the rollers from bending, the rollers working at high temperatures must rotate continuously; when the furnace is empty burned or not discharged, the rollers should swing or rotate at a low speed of 0.5-1.5 cycles per minute. Roller hearth furnace is widely used in normalization, annealing, quenching, tempering and other heat treatment processes because of its fast and uniform heating on both sides of the material.
The utility model relates to a conveyor belt type heat treatment furnace, in which chains are used as conveyor belts to transport workpieces. Chain furnace for heating thin slab before rolling and normalizing thin slab. Chains are usually arranged in grooves under the furnace. There are "claws" made of heat-resistant steel or heat-resistant cast iron between the chains, and thin slab or thin slab are placed on them. Usually the steel can be heated to 900 C and the furnace length is not more than 25 meters. Non-ferrous metal processing, machinery
Heat treatment furnace
In industries such as enamel, chain furnace is also commonly used for heat treatment of various workpieces and drying of castings. Some chains of chain furnace are installed on the top or side of the furnace. The hook or hanger rod is inserted into the furnace through the gap to hang the workpiece. Some low-temperature heat treatment furnaces put chains in the furnace, and the workpiece is heated directly on the chains.
Traction heat treatment furnace
It is widely used in tin plating, zinc plating, unfolding continuous heat treatment of silicon steel and stainless steel for cold rolled strip, and in annealing of deep drawing steel strip in recent years. The traction furnace can be divided into horizontal type and vertical type. Horizontal type has one-way (through horizontal furnace) and multi-way (folding furnace); vertical type also has one-way (vertical furnace) and multi-way (tower furnace). Compared with bell furnace, traction heat treatment furnace has the advantages of shorter construction period, less floor space, better product quality (flat, uniform) and higher automation, but the equipment is complex. The speed of towing strip steel in tower furnace can reach 10 meters per second. It can be heated by radiation tube or electric heater, and the composition can be controlled. The treatment temperature is 700-980 C.
Steel wire lead quenching furnace
Patenting furnace is a kind of traction heat treatment furnace, which is used for heating steel wire before medium temperature quenching in lead trough. The heating temperature is 870-970 C. There are three types of furnaces: muffle type, open fire type and direct electric heating type. In addition, well furnace is often used for heat treatment of large workpieces, wheels, tyres, etc. Bath furnaces are widely used in heat treatment of small parts requiring uniform and rapid heating and preventing oxidation and decarbonization.