Nitriding furnace is a kind of equipment which can ionize the thin nitrogen gas in the direct current electric field in the vacuum vessel, form nitriding layer on the surface of metal parts by the positive ion bombardment, so as to achieve the surface hardening. Nitriding furnace has remarkable nitriding effect on nodular cast iron, alloy steel, stainless steel, P / M products, titanium alloy, high speed steel, tool steel, etc.　

The nitriding furnace is composed of furnace body, transmission device, vacuum obtaining system, power supply system, gas supply system temperature measurement.

1. The furnace body is composed of furnace cover, barrel, furnace chassis underframe, among which the interlayer of furnace cover, barrel furnace chassis is provided with cooling water, the furnace is equipped with stainless steel alloy aluminum double-layer heat insulation screen, the furnace body is equipped with double-layer tempered glass for observing the situation in the furnace during the ion nitriding process.

2. The furnace cover is equipped with two sets of cathode power transmission devices one set of thermocouple hanging column. The hanging plate is installed on the furnace cover. The user shall design the lifting appliance according to the processed parts lift the workpiece on the hanging plate through the lifting appliance.

3. The vacuum obtaining system of the furnace body is generally composed of two rotary vane vacuum pumps a pipeline system with a disc valve in series. The disc valve is used to adjust the air extraction rate by closing rotating different angles to maintain the pressure in the furnace under different air intake conditions. The vacuum value is read out by a matching vacuum gauge for the measurement of the vacuum degree.

4. The air supply pipe inlet of the furnace body is set on the shell body, one Rotameter for hydrogen calibration / nitrogen calibration respectively

5. The thermocouple is inserted into the furnace through the hanging column with thermocouple for analog measurement. The temperature is recorded by the instrument controlled by P, I D.

Three phenomena of heat treatment temperature in multi-purpose furnace

1. General overheating: if the heating temperature of heat treatment is too high the holding time is too long under high temperature, the coarsening of austenite grains is called overheating. The coarse austenite grain will reduce the strength toughness of the steel, increase the brittleness transition temperature, increase the deformation cracking tendency during quenching. The cause of overheating is out of control of furnace temperature instrument mixture (often without understanding the process). After annealing, normalizing multiple high temperature tempering, the overheated structure can be re austenitized to refine the grains under normal conditions.

Fracture heredity: the steel with overheated structure after heat treatment can refine austenite grain after reheating quenching, but sometimes it still has coarse granular fracture. There are many theoretical controversies on the generation of fracture genetic. It is generally believed that MNS other impurities were once dissolved into austenite enriched in the crystal interface due to high heating temperature, these inclusions would precipitate along the crystal interface when cooling, easily fracture along the coarse austenite grain boundary when impacted.

3. Heredity of coarse structure: when the steel with coarse martensite, bainite widmanstatten structure is re austenitized, the austenite grain is still coarse when it is heated slowly to the normal quenching temperature, even lower, which is called heredity of structure. In order to eliminate the heredity of coarse structure, intermediate annealing multiple high temperature tempering can be used.

The above is a multi-purpose furnace manufacturers to introduce the relevant content, I hope to help you.