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What are the Chinese design standards for heat exchanger tubesheet?

The tube plate is one of the main parts of the shell and tube heat exchanger. The reasonable design of the tube plate is important for the correct selection and saving of materials, reducing the difficulties of processing and manufacturing processes, reducing costs and ensuring safety in use. Therefore, the strength of the tube plate must be properly analyzed to reasonably determine the thickness of the tube plate. GB151 “heat exchanger” for the design and manufacture of shell and tube heat exchangers, inspection and acceptance of a set of technical requirements must be followed. As a whole, the heat exchanger […]

2022-04-03

What is quenching bending?

1. Why does quenching bending occur? Quenching bending occurs during heating and quenching cooling. Sagging bending occurs during heating, and the reason for bending during cooling is uneven cooling. The faster the cooling speed is, the easier it is to make the cooling uneven. Therefore, the water cooling is most prone to quenching bending, and then gradually reduce according to the order of oil, hot bath and air (cooling). If the cooling is uneven, the side of the rapid cooling initially becomes concave, and when the whole part is cooled, it reverses to become convex. In addition, the use of […]

2022-03-05

Cause analysis of surface defects of 316L stainless steel cold rolled plate

Aiming at the linear defects on the surface of 316L stainless steel cold rolled plate, the chemical composition analysis, metallographic analysis, scanning electron microscope and energy spectrum detection of continuous casting billet, hot rolled black coil and cold rolled plate were analyzed. The results show that the surface of 316L stainless steel continuous casting billet with defects has deep vibration marks, pits and microcracks; There are linear defects on the surface of hot rolled plate, and there is a large area of oxidation area near the defects; No inclusions with large size were found at the defects of cold rolled […]

2022-02-22

Process instruction for pickling and passivation of 316L austenitic stainless ……

General Austenitic stainless steel has good corrosion resistance and good cold and hot working performance, so it is widely used to manufacture all kinds of pressure vessels with anti-corrosion requirements. The passive film on the surface of austenitic stainless steel has a great influence on its corrosion resistance. The passive film of austenitic stainless steel is mainly obtained by pickling and passivation. Principle of pickling and passivation The phenomenon that the corrosion rate of metal after treatment with oxidizing medium is significantly lower than that before treatment is called metal passivation. The passivation mechanism can be explained mainly by the […]

2022-02-21

Performance difference of Q345A, Q345B, Q345C, Q345D and Q345E steels

Q345 is a kind of steel material. It is a low alloy steel (C < 0.2%), which is widely used in buildings, bridges, vehicles, ships, pressure vessels, etc. Q represents the yield strength of this material. The following 345 refers to the yield value of this material, which is about 345MPa. The yield value will decrease with the increase of material thickness. Q345 has good comprehensive mechanical properties, acceptable low-temperature performance, good plasticity and weldability. It is used as structures, mechanical parts, building structures and general metal structures bearing dynamic loads such as medium and low-pressure vessels, oil tanks, vehicles, […]

2022-02-02

Selection of stainless steel welding materials for pressure vessels

Stainless steel for pressure vessel and its welding characteristics The so-called stainless steel means that after adding a certain amount of chromium into the steel, the steel is in a passive state and has the characteristics of no rust. To achieve this, the chromium content must be more than 12%. In order to improve the passivation of steel, nickel, molybdenum and other elements that can passivate steel often need to be added to stainless steel. Generally speaking, stainless steel is actually the general name of stainless steel and acid resistant steel. Stainless steel is not necessarily acid resistant, but acid […]

2022-01-06

Bolted flange connection structure of flange design

There are many forms of removable sealing devices for pressure vessels, such as threaded connection, socket connection and bolt flange connection in medium and low pressure vessels, among which bolt flange connection with simple structure and convenient assembly is the most common. Bolted flange connection is mainly composed of flange, bolt and gasket, as shown in Figure 1. Figure 1 Bolted flange link structure The bolt has two functions: one is to provide pre tightening force to realize initial sealing and maintain the sealing during operation; The second is to change the bolted flange connection into a detachable connection. The gasket […]

2021-12-09

Pressure test of natural gas pipeline

For the pressure test of natural gas pipeline, the strength and tightness pressure test of the project is generally carried out in sections according to the requirements of the design drawings and the actual situation of the site. Clean water is selected as the pressure test medium. The following is a brief description of pressure test of large diameter and long-distance natural gas pipeline. Construction procedure Preparation ➡ Clean the pipe ➡ Measure the diameter of the pipe ➡ Sheung Shui ➡ strength test ➡ Tightness test ➡ Sweep water ➡ end Preparation Preparation of pressure test scheme (1) Sectional […]

2021-11-02

What is a seamless steel pipe for three chemicals

What is a seamless steel pipe for three chemicals? Seamless steel pipe used in petroleum, petrochemical and chemical industries(contain coal chemical industry) what say normally namely 3 change use seamless steel pipe, point to petroleum chemical industry commonly, include petroleum refining to change, chemical fiber production, coal chemical industry, chemical industry, chemical fertilizer production uses steel pipe aggregate. According to the production mode of steel pipe, it is divided into seamless steel pipe and welded pipe. Can be divided into carbon steel pipe, alloy steel pipe and stainless steel pipe by steel, and the compound steel pipe widely used in recent […]

2021-10-05

Application of nickel base alloy Inconel 690 in coal to methanol process pipel……

In the coal to methanol production unit, the pipeline from the heating furnace to the reformer is used to transport the mixture of gas and steam under high temperature and high pressure. The material for manufacturing this pipeline is required to have lasting strength, oxidation resistance and vulcanization resistance under high temperature and high pressure. The mixture of gas and steam is a flammable and explosive medium, which is very dangerous. It is required that the pipeline conveying this medium must be safe. The nickel base alloy inconel 690 is an ideal material for manufacturing this kind of nickel base […]

2021-09-03

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Industry News

What are the Chinese design standards for heat exchanger tubesheet?

What is quenching bending?

Cause analysis of surface defects of 316L stainless steel cold rolled plate

Process instruction for pickling and passivation of 316L austenitic stainless ……

Performance difference of Q345A, Q345B, Q345C, Q345D and Q345E steels

Selection of stainless steel welding materials for pressure vessels

Bolted flange connection structure of flange design

Pressure test of natural gas pipeline

What is a seamless steel pipe for three chemicals

Application of nickel base alloy Inconel 690 in coal to methanol process pipel……