The classification and characteristics of grooved pipe fittings are as follows:

 

The different diameter elbow has the best pressure-resisting function. However, due to various factors, the practical wall thickness of floor heating pipes is generally the same, and under this wall thickness, all kinds of pipes can satisfy the needs of floor heating, and the pressure-resistant advantages of different-diameter elbow pipes can not be shown; thermal conductivity: the demand of pipes for floor heating has good thermal conductivity, low-temperature thermal shock resistance and low-temperature shock resistance function ratio. Better.

 

I. Production Specification for Elbows with Different Diameters

 

Elbows are now the universal norms in the world. The national norms of the United States are ANSIB16.9 and 16.28. The outer diameter scale of this code is 1/2 ~80, generally within 24 seamless steel tube is used as raw material, 26 to 80 are stamped with steel plate and welded in the future. The maximum wall thickness is 60 mm and the minimum is 1.24 mm. Carbon steel (20 #), alloy steel and stainless steel are the most commonly used steels, with a total of 24 steels. The CrMo steel used on boilers is like 15Cr, and the amount is relatively large. Three-way, external diameter scale is 2.5 -60, from 26 -60 for welding three-way. The wall thickness is 28-60 mm. The standard size of big head and small head is generally referred to as big head standard first, then small head standard. The minimum size of big head is 0.75, the minimum size of small head is 0.5, the maximum size of big head is 60, the maximum size of small head is 48, 20-60 is welded, and the wall thickness is 2.8-4.5mm.

 

2. Processing Skills of Elbows with Different Diameters

 

With the continuous development of the world economy and the continuous improvement of income level, our policy is to face the world's leading construction and shipping industries and other related professions. Stamping elbows are mainly Title receivers. They can take on a heavy burden in the development of this commodity, and have the world-class skills and start sailing. Stamping elbow pipe processing skills have certain skills, according to certain skills in the production of different-diameter elbow can only do small caliber, if the pipe standard is too large, it is difficult to buy finished products of different-diameter elbow, can only use welding elbow. Because there are more welds in the welding elbow, the function of all applications is not as good as that of the Non-diameter elbow, which is simply corroded and leaked. And because the different diameter elbow is produced in batches, the price is cheaper than that of welded elbow. Now there are investment casting elbows, can do 316L, corrosion resistance is very good.

 

Because most of the pipe fittings are used for welding, in order to improve the welding quality, the end of the car is grooved, leaving a certain point of view, with a certain side, this demand is more stringent, how thick the edge is, how many viewpoints and the scale of error are specified. Surface quality and mechanical function are fundamentally the same as those of pipes. For welding convenience, the fittings are the same as the steel of the joined pipe.

 

The different-diameter elbow is made of malleable cast iron. It is used in connection of water supply pipeline, steam pipeline, gas pipeline and oil pipeline. It has black color, right-angle bending, good quality and wear resistance. It is not easy to damage the different-diameter elbow. The standard is 1/2-10 inch. Commodities are widely used in petroleum, chemical, metallurgical and electric industries. Pipeline installations, installations, matching and equivalent labor. The inspection results of different diameter elbows and the thickness of push elbows were checked by thickness gauge. The radius of curvature, the diameter of port section and the machining allowance of length were checked by channel marking method. The acceleration of the pushing speed is 15 mm per minute and the radius of curvature is increased by 50 mm, that is, the pushing speed is accelerated and the radius of curvature is increased.

 

Abrasion of elbows with different diameters has always been an important factor affecting safe and civilized production. With the continuous development of scientific skills, data are constantly innovative, showing materials such as cast stone, cast steel, alloy, centrifugal casting composite ceramics and so on. In the course of scientific development, different-diameter elbows have been planned accordingly. According to the corresponding skills and functions, the alumina ceramics lined with pipelines have become one of the most widely used wear-resisting materials with its high wear resistance, high hardness, oxidation resistance, good corrosion resistance and extremely high high high and low temperature strength. The market share of special ceramics (wear-resistant materials) is 80%.

 

3. Advantages of Manufacturing Skills for Elbows with Different Diameters

 

1. Non-diameter elbows are suitable for piping systems of petroleum, natural gas, chemical industry, hydropower, construction and boiler industries.

 

2. Without using billet as raw material, the cost of pipe-making equipment and die can be saved. Carbon steel elbows with large diameter and relatively thin wall thickness can be obtained arbitrarily.

 

3. Because of the above two reasons, the manufacturing cycle can be shortened and the production cost can be greatly reduced. Because no special equipment is needed, it is especially suitable for processing large carbon steel elbows on site.

 

4. The blank is flat or developable surface, so the blanking is simple, the precision is simple and the assembling and welding is convenient.

 

With the help of the power of conventional or special stamping equipment, the different-diameter elbow can directly deform the sheet metal in the die and obtain the production skills of the commodity parts with certain shape, size and function. The sheet metal, die and equipment are the three elements of stamping. Stamping is a method of metal cold deformation processing. It is called cold stamping or sheet metal stamping, or stamping for short. It is one of the main methods of metal plastic processing, and also belongs to data forming engineering skills.

 

IV. Functions of Elbows with Different Diameters

 

1. Long-term pressure withstanding function, only in terms of planning stress, the pressure withstanding function of the national standard elbow with different diameters is the best. However, due to various factors, the practical wall thickness of floor heating pipes is generally 2 mm. Under this wall thickness, all kinds of pipes can satisfy the needs of floor heating, and the pressure resistance of elbow pipes with different diameters can not be demonstrated.

 

2. Thermal conductivity: Pipes for floor heating need good thermal conductivity.

 

3. Low-temperature heat shock resistance: PE-RT and PE-EX have better low-temperature shock resistance. Pipes are not easily impacted and cracked during construction in winter, which increases the flexibility of construction organization.