Heat treatment of the sealing surface of carbon steel gate valve
Addtime：2020-06-29 From： View：455
The heat treatment of the sealing surface of the carbon steel gate valve refers to the heat treatment of the carbon steel valve body and the gate plate that are welded with cobalt-chromium-tungsten hard alloy sealing surfaces. After the cobalt-chromium-tungsten hard alloy sealing surfaces are welded onto the carbon steel gate valve, a stress-relieving annealing process should be carried out. The main purpose of this is to remove the residual stress generated during the welding process and improve the mechanical processing performance.
For the valve with a carbon steel base material, which is welded with CoCrW hard alloy, SF-4(137) alloy, or sprayed with WF330 or Fe30, the stress-relieving annealing heating temperature is selected based on the base material carbon steel. Generally, it is 600 - 650℃. The holding time depends on the effective thickness of the part. Generally, it is 1h for every 25mm, with a minimum of 2 hours. After the holding, it is cooled in the furnace to 300℃ and then taken out for air cooling.
Due to the different media that carbon steel gate valves are suitable for, different materials for the welded sealing surfaces can be selected. Gate valves suitable for water, steam, petroleum and its products usually use Cr13 type stainless steel for welding, but some factories also use chromium-manganese alloys (85 alloy or 137 alloy), copper alloys and iron-based alloys for welding.
Welding materials can be divided into two categories based on the different effects of heat treatment. One category is represented by cobalt-chromium-tungsten hard alloys, whose hardness generally cannot be changed by heat treatment, and the hardness of the sealing surface is guaranteed by the welding material. The other category is represented by Cr13 type stainless steel, whose hardness can be changed by heat treatment, and the hardness of the sealing surface (generally required to be 38-44 HRC) can be achieved through heat treatment.
Yuhete Valve Industry is dedicated to the construction of valves in the environmental protection and energy sectors. Protecting the environment and conserving energy.
Yuhete Valve's main application fields: water treatment, sewage and sludge treatment, flue gas desulfurization and denitrification, air treatment and purification, and waste management.
For the valve with a carbon steel base material, which is welded with CoCrW hard alloy, SF-4(137) alloy, or sprayed with WF330 or Fe30, the stress-relieving annealing heating temperature is selected based on the base material carbon steel. Generally, it is 600 - 650℃. The holding time depends on the effective thickness of the part. Generally, it is 1h for every 25mm, with a minimum of 2 hours. After the holding, it is cooled in the furnace to 300℃ and then taken out for air cooling.
Due to the different media that carbon steel gate valves are suitable for, different materials for the welded sealing surfaces can be selected. Gate valves suitable for water, steam, petroleum and its products usually use Cr13 type stainless steel for welding, but some factories also use chromium-manganese alloys (85 alloy or 137 alloy), copper alloys and iron-based alloys for welding.
Welding materials can be divided into two categories based on the different effects of heat treatment. One category is represented by cobalt-chromium-tungsten hard alloys, whose hardness generally cannot be changed by heat treatment, and the hardness of the sealing surface is guaranteed by the welding material. The other category is represented by Cr13 type stainless steel, whose hardness can be changed by heat treatment, and the hardness of the sealing surface (generally required to be 38-44 HRC) can be achieved through heat treatment.
Yuhete Valve Industry is dedicated to the construction of valves in the environmental protection and energy sectors. Protecting the environment and conserving energy.
Yuhete Valve's main application fields: water treatment, sewage and sludge treatment, flue gas desulfurization and denitrification, air treatment and purification, and waste management.