suli lee

Thick-walled seamless steel pipes are widely used in vehicles, airlines, crude oil, chemical plants, engineering construction, heating furnaces, military and other units, and have a significant impact on the social economy. With the development trend of my country's economy, the application field of thick-walled seamless steel pipes has continued to develop, the production scale and specifications have been greatly improved, and the requirements for product quality have become higher and higher. Therefore, thick-walled seamless steel pipes need to pass strict inspections before they leave the factory to meet the requirements of use. The manufacturing level of thick-walled seamless steel pipes should consider the sales market and support the corresponding mechanical equipment. In the whole process of forging and cold rolling of seamless welded thick-walled seamless steel pipe of stainless steel plate, one of the main performance indicators considering the quality of seamless ... Continue reading →

Common defects of steel pipes are roughly divided into five categories: chemical composition deviation, dimensional deviation, appearance irregularity, abnormal physical properties and abnormal process performance. 1. The chemical composition of steel generally refers to the verified smelting composition obtained by sampling and analysis after smelting, and the verified composition that can be sampled for verification and analysis after processing. The verification ingredients should be within the allowable deviation range specified in the corresponding standard. 2. The size of the steel pipe mainly refers to the wall thickness and diameter, and the diameter is divided into outer diameter and inner diameter, as well as the diameter deviation (ovality) of the same diameter. Relevant standards stipulate the allowable deviation of the diameter (outer diameter or inner diameter) and wall thickness of the steel pipe. The allowable deviation of the inch of the steel pipe of different ... Continue reading →

To roll a solid tube blank into a hollow finished steel tube, no matter what method of perforation and tube rolling is used, the processing process for producing a seamless steel tube is the same, which can be basically divided into the following steps:   (1) Billet preparation.  Including billet storage, billet inspection and surface cleaning, billet cutting and cold centering of billet.   (2) The tube blank is heated.  The tube blank is heated by an annular heating furnace. After the tube blank is released from the furnace, it is generally sent to the perforation process through thermal centering.   (3) Perforation.  Perforation is to pierce a solid tube blank into a hollow capillary tube. The thermal size and uniformity required for the inside and outside of the capillary. It will directly affect the quality of the finished product, so it is very important to correctly select the perforation method according to the technical requirements of ... Continue reading →

The advantages of galvanized seamless steel pipe: 1. High pressure resistance: hot-dip galvanized seamless pipe can withstand higher pressure 2. Long average service life: paints with an average adhesion of 500g/m2 can be kept for more than 50 years without maintenance in dry and suburban environments. 3. No maintenance required during use: Hot-dip galvanized seamless pipes have excellent weather resistance and long service life, and require no maintenance costs. Compared to painting, it requires regular maintenance, which saves a lot of money and social costs. 4. Good sturdiness, can withstand mechanical damage from handling and lifting: The galvanized layer is an alloy structure with very good hardness and mechanical properties. 5. Local damage or minor defects are still protective: Since zinc is more chemically active than iron, even minor defects can protect exposed steel, which is the protective property of sacrificial anodes. 6. Comprehensive protection, no dead angle: the ... Continue reading →

Steel pipes can be divided into two categories according to the production method, one is seamless steel pipes, the other is welded steel pipes, and welded steel pipes are straight seam welded pipes. The welded steel pipe can be further divided into high frequency welded pipe (ERW) and double-sided submerged arc welded pipe according to the welding method. First of all, let's focus on the high-frequency welded pipe (ERW): The diameter of the high-frequency welded pipe is usually relatively small, and there is no need to pass the welding wire, so the possibility of cracking during expansion is small. From the point of view of welding speed, for small outer diameter, such as less than 1 inch, the maximum speed can reach 200 m/min. There are usually two ways of crimping, one is welding, the other is fusion welding, the former has less impact on the steel pipe. High-frequency welding is the first one to take. Welding the welded pipe from the processing point of view is ... Continue reading →

What is thick wall steel pipe? The steel pipe with the ratio of the outer diameter of the steel pipe to the wall thickness is less than 20 is called the thick-walled steel pipe.   Application of thick-walled seamless steel pipe:  Mainly used as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural pipe for automobile, tractor, aviation, etc. Manufacturing process of thick-walled seamless steel pipe: Hot rolling (extruded seamless steel pipe): round tube billet → heating → perforation → three-roll cross-rolling, continuous rolling or extrusion → pipe removal → sizing (or diameter reduction) → cooling → straightening → hydraulic test (or flaw detection)→marking→warehousing The raw material for rolling seamless tubes is a round tube blank, which is cut by a cutting machine into a billet with a length of about 1 meter, and sent to a furnace for ... Continue reading →

Seamless steel pipe VS Precision steel pipe:   1. The main feature of seamless steel pipe is that it has no welds and can withstand greater pressure. Products can be very rough as-cast or cold drawn. 2. Cold-drawn precision steel pipes are products that have appeared in recent years, mainly because the inner hole and outer wall dimensions have strict tolerances and roughness. Features of cold drawn (rolled) precision steel pipes: 1. Smaller outer diameter 2. High precision and small batch production 3. The cold drawn (rolled) finished product has high precision and good surface quality 4. The cross-sectional area of the steel pipe is more complicated 5. The steel pipe has better performance and the metal is denser. Main features of precision seamless steel pipe: The inner and outer walls of the steel pipe have high precision and high smoothness. After heat treatment, the steel pipe has no oxide layer. High cleanliness, high pressure steel pipe, no deformation after ... Continue reading →

"Order" is the beginning of cooperation between supply and demand. In order to obtain steel pipes that meet the requirements of the buyer, and the supplier to produce steel pipes that meet the requirements of the buyer, the two parties must fully communicate and exchange in the "ordering" link. 1. First selection and calibration: the orderer should determine the type of steel pipe according to the working state and use requirements of the steel pipe, whether it is a seamless steel pipe or a welded steel pipe. The working state of the steel pipe in use: whether it is used to transport fluid (including the state and properties of the fluid), or used as a mechanical component, the name and standard number that the steel pipe should meet, and pay attention to the "scope of application" of the standard. Determine whether it meets your own use requirements as the basis for delivery;   2. According to the "order content" (ie "order ... Continue reading →

The ultrasonic probe can realize the mutual conversion between electric energy and sound energy, and the physical characteristics of ultrasonic waves when they propagate in elastic media are the basis of the principle of ultrasonic flaw detection of seamless steel pipes. The directionally emitted ultrasonic beam encounters defects when propagating in the tube, causing both wave reflection and wave attenuation. After the signal processing of the flaw detector, if the reflection method is used for flaw detection, the defect echo signal can be obtained, and if the penetration method is used for flaw detection, the defect signal can be obtained by the attenuation of the transmitted wave. Both can give quantitative defect indications by the instrument. Different types of ultrasonic waves can be excited in the tube using the piezoelectric effect or the principle of electromagnetic induction. Therefore, both piezoelectric ultrasound and electromagnetic ultrasound can be used for ultrasonic ... Continue reading →

From the perspective of the mechanism, it is generally believed that the non-metallic inclusions in the tube blank will destroy the continuity and compactness of the structural seamless steel pipe, and serious inclusions may even cause delamination inside the structural seamless steel pipe. Another is hydrogen-induced cracking, that is, due to the accumulation of hydrogen in the steel, the partial pressure of the gas inside the metal is too high, and white spots are formed in the round tube blank. During the rolling process, the cracks expand, and finally delamination defects are formed. In addition, the stress generated by the uneven deformation of the two-roll cross-rolling piercing exceeds the plastic strength, which can also cause delamination. In the case of strict smelting control, the third situation often occurs, and the control measures are: 1. Improve the plastic toughness of structural steel pipes Improve the cleanliness of molten steel and reduce harmful inclusions; ... Continue reading →

The gloss of the annealed seamless steel pipe determines the quality of the product. There are also many influencing factors. Here are five key factors: 1. Annealing temperature. Is the annealing temperature the required temperature? The steel heat treatment process generally adopts the heat treatment and tempering heat treatment process, that is, "annealing" as we usually say, and the temperature range is 1040~1120 °C (Japanese standard). According to the observation hole of the annealing furnace, the stainless steel pipe in the annealing area should be in the condition of incandescent lamp, but there is no softening and relaxation. 2. Annealing atmosphere. Generally, pure hydrogen is used as the annealing atmosphere. The purity of the atmosphere is above 99.99%. If the other part of the atmosphere is a rare gas, the purity can be lower, but it must not contain too much CO2 and water vapor.  3. Furnace wall airtightness. The thick-walled seamless steel ... Continue reading →

1. Structural seamless pipe (GB/T8162-2008) is a seamless pipe for general structure and mechanical structure. 2. Seamless pipe for fluid transportation (GB/T8163-2008) is a general seamless pipe used to transport water, oil, gas and other fluids. 3. Seamless pipes for low and medium pressure boilers (GB3087-2008) are used to manufacture superheated steam pipes, boiling water pipes, and superheated steam pipes, large smoke pipes, small smoke pipes and arch bricks for low and medium pressure boilers of various structures. Hot-rolled and cold-drawn (rolled) seamless pipes of high-quality carbon structural steel for pipes. 4. Seamless tubes for high pressure boilers (GB5310-2008) are high-quality carbon steel, alloy steel and stainless heat-resistant steel seamless tubes used to manufacture the heating surface of water-tube boilers with high pressure and above. 5. High-pressure seamless pipe for fertilizer equipment (GB6479-2000) is a high-quality carbon structural steel and ... Continue reading →

Bearing seamless steel pipe is also called high carbon chromium seamless steel pipe, the carbon content WC is about 1%, and the chromium content WCr is 0.5%-1.65%. Bearing seamless steel pipe is further divided into high carbon chromium bearing seamless steel pipe, chromium-free bearing seamless steel pipe, carburized bearing seamless steel pipe, stainless steel bearing seamless steel pipe, medium and high temperature bearing seamless steel pipe and anti-magnetic bearing seamless steel pipe. kind. High-carbon chromium bearing seamless steel pipe GCr15 is the largest bearing seamless steel pipe in the world. The carbon content of WC is about 1%, and the chromium content of WCr is about 1.5%. Since its birth in 1901 to the present for more than 100 years, the main components are basically no Change, with the progress of science and technology, research work continues, product quality continues to improve, accounting for more than 80% of the world's total production of bearing ... Continue reading →

The impact toughness of the high-pressure seamless boiler pipe reflects the resistance of the metal to the external impact load. It is generally expressed by the impact energy (Ak), and its unit is J (joule). The impact energy test of high-pressure seamless pipe is divided into three types: normal temperature, low temperature and high temperature impact test due to different test temperatures; according to the shape of the sample notch, it can be divided into two types: "V"-shaped notch and "U"-shaped notch impact test. Impact test: use a high-pressure seamless pipe sample of a certain size and shape (10×10×55mm) (with a "U" or "V"-shaped notch in the middle of the length direction, the notch depth is 2mm) to be impacted on the specified testing machine Experiment of breaking from the notch under load impact. High-pressure seamless tube (smls pipe) shock absorption work Akv(u)--the work absorbed by a metal pattern with a ... Continue reading →

Seamless steel pipe (smls) is composed of various elements in steel. These elements are combined in different proportions to form different mechanical properties of seamless steel pipes. The amount of any element will directly affect the mechanical properties of seamless steel pipes. So what role do these elements play in the composition of steel? Let's take a look at the elements that affect the performance of seamless steel pipes:   Carbon (C) When the carbon content increases, the yield point and tensile strength increase, but the plasticity and impact properties decrease. Too high carbon content will easily lead to unqualified intergranular corrosion. The boundary between steel and iron is controlled by the carbon content: <2.11% is steel. Silicon (Si) Silicon is a deoxidizer and desulfurizer with high strength and hardness, which can improve the hot workability of steel. Chromium (Cr) Chromium significantly increases the strength, hardness and wear resistance of ... Continue reading →

What is thick wall steel pipe? Thick-walled steel pipe, the steel pipe with the ratio of the outer diameter of the steel pipe to the wall thickness is less than 20 is called the thick-walled steel pipe. Mainly used as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural pipe for automobile, tractor, aviation, etc. The biggest difference between thick-walled steel pipes and thin-walled steel pipes is the thickness of the steel pipe wall. Generally speaking, thin-walled steel pipes are cold-drawn technology, while thick-walled steel pipes and thick-walled steel pipes generally use hot-rolling technology, if they are distinguished by units of measure. , then, it is generally believed that the wall thickness/pipe diameter equal to 0.02 is the watershed between thick-walled steel pipes and thin-walled steel pipes, those with wall thickness/pipe diameter less than 0.02 are thin-walled steel pipes, and those ... Continue reading →

GB5310 high-pressure boiler seamless pipes are commonly used in superheated steam pipes, heat exchangers and pipes for high-pressure equipment of high-pressure or ultra-high pressure boilers, and have high requirements for welding. Common process, if the welding quality is not good, it will affect the use effect of the pipe. Therefore, when welding the GB5310 high-pressure boiler seamless steel pipe with stable performance, it is necessary to do a good job in the group name inspection of the pipe, and also choose and GB5310. The high-pressure boiler seamless steel tube requires the same electrode for welding, so as to ensure that the GB5310 high-pressure boiler tube has a satisfactory welding quality.   1. Do a good job of quality inspection before welding   In order to ensure the welding quality of GB5310 high-pressure boiler seamless steel pipe, it should be checked before welding to ensure that the surface of GB5310 high-pressure boiler seamless steel pipe has no ... Continue reading →

 1. Common media for pickling of seamless steel pipes (smls)   Sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid. Be sure to add a pickling corrosion inhibitor during pickling to prevent acid corrosion of metals. 2. Pickling process of seamless steel pipe There are mainly dipping pickling method, spray pickling method and acid paste rust removal method. Generally, the dipping and pickling method is used, and the spray method can be used in mass production. Steel parts are generally pickled in 10% to 20% (volume) sulfuric acid solution at a temperature of 40°C. When the iron content in the solution exceeds 80g/L and the ferrous sulfate exceeds 215g/L, the pickling solution should be replaced. Under normal temperature, pickling steel with 20% to 80% (volume) hydrochloric acid solution is not easy to cause excessive corrosion and hydrogen embrittlement. Since the acid has a great corrosion effect on the metal, it is necessary to add a corrosion inhibitor. ... Continue reading →

Seamless steel pipe(smls) is currently the most widely used pipe material. It is generally used for chemical pipelines, petroleum pipelines, natural gas pipelines, water pipelines and other projects that require anti-corrosion treatment. The common seamless steel pipe anti-corrosion processes mainly include 3PE anti-corrosion, Epoxy coal tar pitch anti-corrosion, epoxy resin anti-corrosion, IPN8710 anti-corrosion, cement mortar anti-corrosion technology, etc. 1.Why are seamless steel pipes anti-corrosive? Seamless steel pipe is a relatively high-end steel pipe, and the price is very expensive, but after all, the raw material is also iron, which will also grow rust, which also affects the service life in the pipeline. Therefore, the anti-corrosion of seamless steel pipe must also be done before pipeline construction. One process, for seamless steel pipes is mainly 3pe anticorrosion or epoxy coal tar anticorrosion. The following is an introduction to the precautions ... Continue reading →

Seamless steel pipes (SMLS pipe), longitudinally welded steel pipes (LSAW pipe), forged steel pipes, precision dense steel pipes, high-precision precision steel pipes, and other steel pipes will cause the steel pipe body to bend to varying degrees in the longitudinal direction (that is, the length direction) during the production process. However, the degree of bending of some steel pipe products is visible to the naked eye, and the steel pipe is not a qualified product. As long as it is a regular manufacturer, such products are absolutely not allowed to leave the factory, and some require special equipment to measure straightness. For the straightness of steel pipes, the requirements are not high in general fluid transportation pipelines. This kind of pipe mainly requires the concentricity of the nozzles to facilitate the welding of the pipeline. However, if steel pipes are used in processing machinery and equipment, especially rubber rollers, middle shafts, etc., they have higher ... Continue reading →