A brief introduction to Thread Flange

 Thread Flange, Screw Flange, NPT Flange

Size range: 1/2 to 6 inches (DN 15 to DN 150)

Pressure range: ANSI class 150 to 600

Surface Treatment: Black Coating, Color Coating, Hot Dipped Galvanized, or per customer

Standard: ANSI B16.5, BS4504, EN1092-1, DIN

Materials:

ASTM A105, A350 LF2 (CS)

ASTM A182 F304/304L, F316/316L, F316H, F310, F321 (SS)

ASTM A182 F11, F22 (AS)

For more info about carbon, stainless steel, and alloy thread flange, you can contact Xinyue online directly, our send your questions to Contact Us---Email. We’ll be at your service.

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Flattening test of seamless steel pipe

 The production process of seamless steel pipes is relatively cumbersome and rigorous. After the seamless steel pipe is produced, certain tests must be carried out. Do you know the flattening test method and steps of the seamless steel pipe?

1) Flatten the sample:

1. The sample is cut from any part of the seamless steel pipe that has passed the visual inspection, and the sample should be the full-face pipe section of the pipe product.

2. The length of the sample should not be less than 10mm, but not more than 100mm. The edges of the specimen may be rounded or chamfered by filing or other methods. Note: If the test results meet the test requirements, the edges of the sample may not be rounded or chamfered.

3. If it is to be carried out on the end of a full-length tube. During the test, the incision shall be made perpendicular to the longitudinal axis of the pipe at the length of the sample from the end face of the pipe, and the cutting depth shall be at least 80% of the outer diameter.

2) Test equipment:

The test can be carried out on a universal testing machine or a pressure testing machine. The testing machine shall be equipped with two upper and lower parallel platens, and the width of the parallel platens shall exceed the width of the flattened sample, that is, at least 1.6D. The length of the pressing plate is not less than the length of the sample. The testing machine has the ability to flatten the sample to a specified pressure value. The platen should have sufficient stiffness and be able to control the speed range required for the test.

3) Test conditions and operating procedures:

1. The test should generally be carried out in the room temperature range of 10°C ~ 35°C. For tests requiring controlled conditions, the test temperature shall be 23°C ± 5°C. The flattening speed of the sample can be

20-50mm/min. When there is a dispute, the moving speed of the platen should not exceed 25mm/min.

2. According to the relevant standards, or the agreement between the two parties, the distance H of the platen should be determined.

3. Place the sample between two parallel platens. The welds of welded pipes should be placed in the positions specified in the relevant products and standards. Use a press or a testing machine to apply a force in the radial direction, and at a speed of not more than 50mm/min, evenly press to the flattening distance H, remove the load, remove the sample, and visually observe the bending part of the sample.

Precautions:

During the flattening test, the flattening distance H shall be measured under load. In the case of closed flattening, the width of the contact between the inner surfaces of the sample should be at least 1/2 of the inner width b of the standard sample after flattening.

The flattening performance test of seamless steel pipe plays an important role in the hardness, melting point, corrosion resistance and pressure of seamless steel pipe, and this test should be done well.

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Galvanizing process of square and rectangular tubes

 A) What are the two galvanizing processes for square and rectangular tubes?

Galvanized square tube, also known as galvanized square tube, is a square tube that has been galvanized. According to different production processes, galvanized square tube can be divided into two types: hot-dip galvanized square tube and cold-galvanized square tube:

1. Hot-dip galvanized square tube

It is a galvanized square tube formed after a series of chemical reactions by placing the square tube in a hot-dip galvanizing bath after being crimped and formed by a steel plate or a steel strip. There are many kinds of hot-dip galvanizing methods, such as wet method, dry method, lead-zinc method, redox method, etc. The main difference between different hot-dip galvanizing methods is what method is used to activate the surface of the pipe body to improve the quality of galvanizing after the steel pipe is acid dipped and cleaned. In the production, dry method and redox method are mainly used.

2. Cold galvanized square tube

Also known as electro-galvanized square pipe, it is to put the made square pipe into the electrolyte, the liquid contains zinc, after electrification, the electroplating operation is carried out, and the zinc powder or galvanized coating and the steel of the square pipe are fully contact to form a galvanized layer.

B) What is the difference between hot dip galvanized square pipe and cold galvanized square pipe?

The main difference between hot-dip galvanized square pipe and cold-dip galvanized square pipe lies in the different production processes. In addition, there are also certain differences in appearance, use, price, etc.

1. Different appearance

The appearance of the cold galvanized square tube is relatively smooth and bright.

The angle is slightly colorful; the appearance of the hot-dip galvanized square pipe is slightly rougher than the cold-galvanized square pipe, and it is silver-white, and the appearance is prone to process water lines and a little dripping tumor, especially in the process of production.

One end of the piece is more obvious.

2. Different anti-corrosion properties

Compared with hot-dip galvanized pipe, cold-dip galvanized pipe has worse corrosion resistance, and the corrosion resistance of hot-dip galvanized pipe is dozens of times that of cold-dip galvanized pipe.

3. Different uses

Hot-dip galvanized square and rectangular pipes are mainly used in curtain walls, construction, machinery manufacturing, solar power generation brackets, steel structure projects, etc., especially in curtain walls and buildings, which are widely used;

Cold galvanized square tube is characterized by high strength and light structure, and is mainly used in general occasions.

4. Different prices

Under the same thickness and size, the price of hot-dip galvanizing is more expensive than that of cold-galvanizing. This is because the cold-galvanized square tube only needs to be plated on one surface, and the whole square tube must be plated with respect to the hot-dip galvanized square tube.For galvanizing, the production cost is naturally lower.Of course, although the difference between the hot-dip galvanized square tube and the cold-dip galvanized square tube is relatively large, there is actually no difference between the two, and the appropriate square tube can be selected mainly according to the actual needs.

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A brief introduction to RTJ Blind Flange

 RTJ blind flange, which is short for ring-type joint blind flanges, is widely applied in oil field, water system, offshore construction, ship manufacturing, sewage treatment, natural gas pipeline system, power plant, etc.

Xinyue can provide size range form 1/2” to 56”, DN 15 to 1400. Pressure of ANSI class is from 150 to 2500.

Most common seen standard is API, ANSI, BS, JIS, UNI, DIN, EN1092-1.

Most common seen material are as below:

ASTM A105

ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2

ASTM A516.60

ASTM A694 (F42, F46, F48, F50, F52, F56, F60, F65, F70)

ASTM A182 F304/304L, F316/316L, F316H, F310, F321

ASTM A182 F11, F22

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Do you really know about Flange?

 Flange can be devided into many kinds, today we’ll talk about the classification of flanges.

Most common seen flange are as below:

1. RTJ Blind Flange

2. WN Flange

3. RF Flanges

4. Thread Flange

5. Plate Flange

6. Socket Welding Flange

7. Slip on Flange

8. Spade flange & Spacer ring Flange

9. Orifice Welded Neck Flanges

Xinyue Steel Group can provide all above flanges, size range of flange is from 2” to 96”, and we can manufacture carbon flange, stainless flange and alloy flange. For more info about flange, you can contact Xinyue anytime, we’ll provide more professional info for you online.

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Long lifespan of ERW steel pipe

 What should we pay heed to when we are about to buy ERW steel pipes? Of course, quality is the first factor we should focus on, then comes the price we should pay attention to, but there is also another factor we should pay attention to-- lifespan of the pipe.

Long service life would be an important factor for a kind of ERW steel pipe when it applied in engineering project as this means saving money to fix it and change it.

Steel pipe, used in water, oil and gas transportation, is necessary to have a relative long lifespan.

As there are advantages for long lifespan: first of all, we should know that it would cost human resource as well as cost if we have to change it often. What’s more, it would influence the basic usage for customers if we change it often which would damage the whole process for customers sometimes.

Plastic or wood pipes would not so strong for the vehicles’ weight when we use them underground. So that steel pipe, with its hardness, is the top choice for this situation. Of course, because of the external corrosion and internal abrasion. The service life of steel pipes would be increased by the usage of proper coating and cathodic protection. With attention to coatings and cathodic protection, the service life of steel pipe can be extended indefinitely.

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Why are there pores in the welds of welded steel tubes?

 Welded steel tube weld pores not only affect the tightness of the pipeline weld and cause pipeline leakage, but also become the induction point of corrosion, which seriously reduces the strength and toughness of the weld.

The factors that cause porosity in the weld are: moisture, dirt, oxide scale and iron filings in the flux, welding components and covering thickness, surface quality of the steel plate, treatment of the edge of the steel plate, welding process and steel tube forming process.

Measures to prevent porosity in welded steel tubes:

1) Flux composition: When the welded steel tube contains an appropriate amount of CaF2 and SiO2, it will react and absorb a large amount of H2 to generate HF with high stability and insoluble in liquid metal, which can prevent the formation of hydrogen pores.

2) The accumulation thickness of the flux is generally 25-45mm. The maximum value of the accumulation thickness of the flux with large particle size and small density, and the minimum value otherwise; the maximum value of the accumulation thickness of high current and low welding speed, and the minimum value otherwise. In addition, in summer or when the air humidity is high, the recovered flux should be dried before use.

3) Surface treatment of steel plate: In order to avoid sundries such as oxide scale falling off from uncoiling and leveling from entering the forming process, a plate surface cleaning device should be installed.

4) Steel plate edge treatment: rust and burr removal devices should be installed at the edge of the steel plate to reduce the possibility of pores. The position of the removal device is best installed after the edge milling machine and the disc shear. The structure of the device is two active wire wheels with adjustable gaps at the upper and lower positions on one side, which press the edge of the plate up and down.

5) Weld profile: the forming coefficient of the weld is too small, the shape of the weld is narrow and deep, the gas and inclusions are not easy to emerge, and it is easy to form pores and slag inclusions. Generally, the welding seam forming coefficient is controlled at 1.3-1.5, the maximum value for thick-walled welded tubes, and the minimum value for thin-walled tubes.

6) Reduce the secondary magnetic field: In order to reduce the influence of magnetic bias blowing, the connection position of the welding cable on the workpiece should be close to the welding terminal, so as to avoid the secondary magnetic field generated by some welding cables on the workpiece.

7) In terms of technology: the welding speed should be appropriately reduced or the current should be increased, so as to delay the crystallization speed of the weld pool metal, so as to facilitate the escape of gas; at the same time, if the delivery position of the strip is unstable, it should be adjusted in time to prevent frequent passes. Fine-tuning the front or rear axle maintains shape, making it difficult for gas to escape.

Welded steel tube refers to a steel pipe made of steel plate or strip steel after being crimped and welded, generally with a fixed length of 6 meters. The production process is simple, the production efficiency is high, the cost is low, and the development is fast, but the strength is generally lower than that of seamless steel pipes.

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