The solid solution furnace for stainless steel pipe of natural gas belongs to a kind of annealing furnace.

Stainless steel is softened by solid solution treatment. Generally, the stainless steel tube is heated to 950 ~ 1150 ℃ for a period of time, so that carbides and various alloy elements are fully and evenly dissolved in austenite, and then rapidly quenched and cooled, so that carbon and other alloy elements can not precipitate in time to obtain pure austenite structure, which is called solid solution treatment.

The continuous solid solution furnace for stainless steel pipe of natural gas is roller hearth continuous heat treatment. Its main structure includes feeding frame, heating furnace, water spray cooling system and discharging frame.

The heating furnace adopts the PID control mode of burner big and small fire, one thermocouple controls two burners, the furnace temperature changes smoothly, the furnace body sealing performance is good, whether in the low temperature control area or in the later stage of heating and insulation, the temperature uniformity of the temperature control thermocouple can be ensured within ± 10 ℃, so as to ensure that the temperature uniformity of the effective heating area meets the process requirements.

The stainless steel tube moves forward continuously through the rotating roller, which is evenly heated, without damage and small deformation. Because the roller in the furnace always rotates in the heating furnace, the heat loss is relatively small, and the thermal efficiency in the furnace is high.

After heating, the stainless steel tube is cooled at a high speed after entering the strong cooling zone (Suzhou jinruier electric furnace independently developed and designed). The purpose is to refine the grain and dissolve the carbide in austenite, improve the toughness and corrosion resistance, eliminate stress and soften, and obtain high-quality products.

There are three functions of solution treatment

1. It is especially important for raw materials to make the microstructure and composition of steel pipe uniform, because the rolling temperature and cooling rate of each section of hot rolled wire are different, resulting in the inconsistent microstructure.

At high temperature, the atomic activity intensifies, the σ phase dissolves, the chemical composition tends to be uniform, and the uniform single-phase structure is obtained after rapid cooling.

2. The work hardening is eliminated to facilitate the continuous cold working.

Through solution treatment, the distorted lattice is restored, the elongated and broken grains are recrystallized, the internal stress is eliminated, the tensile strength of steel pipe is decreased, and the elongation is increased.

3. The corrosion resistance of stainless steel was restored.

Due to carbide precipitation and lattice defects caused by cold working, the corrosion resistance of stainless steel decreases. After solution treatment, the corrosion resistance of the steel pipe returns to the normal state.

For stainless steel pipe, the three elements of solution treatment are temperature, holding time and cooling rate. The solution temperature is mainly determined by chemical composition. Generally speaking, the solid solution temperature should be increased for the brand with many kinds of alloy elements and high content. Especially for the steel with high content of Mn, Mo, Ni and Si, the softening effect can be achieved only by increasing the solid solution temperature and making it fully dissolved.

However, the carbides of stabilized elements, such as 1Cr18Ni9Ti, fully dissolve in austenite at high solution temperature, and precipitate at grain boundaries in the form of Cr23C6 during subsequent cooling, resulting in intergranular corrosion. In order to keep the carbides (TIC and NBC) of stabilizing elements from decomposition and solid solution, the lower solution temperature is generally adopted.

Any question about annealing furnace price can contact our company Suzhou jinruier Electric Furnace Co., Ltd!