After the opening on March 20, the main contract of iron ore fell by nearly 5%, and the disk was always dominated by oscillations, with the largest drop of 5.65%, ending at 5.10%. Market analysts said that the reason was mainly related to the official release of the Danshui Valley on March 19, Brazil, saying that Minas Gerais was partially affected by the mine disaster and the mining area was about to resume production.

Precision spiral steel pipe is a kind of high-precision steel pipe after cold drawing or hot rolling. Because the inner and outer walls of precision spiral steel pipe have no oxide layer precision spiral steel pipe, high pressure and no leakage, high precision, high smoothness, no cold deformation, flaring, flattening without cracks, etc., it is mainly used to produce pneumatic or hydraulic components.

Burn-through and hydrogen-induced cracking in spiral steel pipe welding are hot topics at home and abroad. There are many influencing factors of these problems, including spiral steel pipe body, pre-weld treatment, welding process and post-weld treatment.

With the continuous development of China's economy, the country vigorously develops the energy industry. Pipeline long-distance oil and gas pipelines are an important way of energy security. In the anti-corrosion construction process of oil (gas) pipelines, the surface treatment of anti-corrosion spiral steel pipes determines the service life of pipelines. One of the key factors is the premise that the anti-corrosion layer and the steel pipe can be firmly combined. According to the research institute's verification, the life of the anti-corrosion layer depends on the coating type, coating quality and construction environment. The surface treatment of the anti-corrosion spiral steel pipe affects the life of the anti-corrosion layer by about 50%. Therefore, it should be strictly in accordance with the anti-corrosion layer. Standardize the requirements on the surface of steel pipes, continuously explore and summarize, and continuously improve the surface treatment methods of steel pipes.

　　Skin turning of billets 　　The steel billet is a process for removing the surface defects and scale of the round billet and processing the specified outer diameter and a certain surface finish. The turning amount and turning accuracy are determined by the diameter of the billet and the type of steel. The amount of turning is shown in Table 4-2. The amount of turning varies according to the conditions of each factory, and is roughly in the range of 3.5-15 mm. The turning amount increases as the diameter of the billet increases. Stainless steel has more surface defects than ordinary carbon steel and low alloy steel, and its turning amount is also larger.

The cut steel pipe is inspected according to technical requirements. The inspection includes checking the size and bending of each pipe and the quality of the inner and outer surfaces of the pipe, and sampling the mechanics and process performance, but the inspection requires sampling. The inspection of the geometrical dimensions and bending of the steel pipe can be carried out on the inspection table, or it can be continuously detected by an automatic size detecting device such as laser caliper, thickness measurement, and length measuring instrument.

　　There are many types of steel pipes and different uses, so their technical requirements are different and production methods are different.

　　The intermediate wave is formed at the side of the precision stainless steel strip and half of the center (1/4 inch from the side). The main reason is that the shape of the blank is not good and the intermediate roll shape curve is incorrect or the position is incorrect. The buck is a defect formed by the different English love in the thickness direction of the steel strip. The main reason is the result of the bending of the work rolls in the horizontal direction and the surface condition lubrication conditions of the upper and lower work rolls and the work mixed wear. Its manifestation is that it is rolled up laterally to form a "funnel shape".

　　Since the surface of the stainless steel tube will form a thin protective film, although the protective film is about 3×10-6 mm, it is very tough. Even if it is destroyed, as long as there is oxygen next to it, it can be regenerated immediately to prevent rust. As long as you know the characteristics of stainless steel and use it correctly.

　　The inner diameter of the stainless steel cylinder tube indicates the output force of the cylinder. The piston should slide smoothly in the cylinder, and the inner surface roughness of the cylinder should reach ra0.8um. The inner surface of the steel pipe column should be plated with hard chrome to reduce friction and wear and prevent corrosion. The cylinder material is made of high-strength aluminum alloy and brass, except for high-carbon steel pipes. This small cylinder is made of stainless steel. In corrosive environments, cylinders using magnetic switches or cylinders should be made of stainless steel, aluminum or brass.

What are the main factors affecting the service life of anti-corrosion insulation steel pipe ?

What should I pay attention to in the transportation of anti-corrosion insulation steel pipe ?

The demand for steel is difficult to release, and there is limited room for incremental demand for cold drawn steel pipe in the future.

From the demand trend, from January to May 2018, fixed-asset investment, real estate investment, and infrastructure investment all experienced different degrees of decline.

There are a series of regulations and requirements for anti-corrosion and marking of welded pipes. The specific requirements for the logo are as follows:

Construction welded steel pipe and steel: On the 7th, the overall price of domestic building materials fell.

Today, the price of construction welded pipes has risen markedly. The average price of rebar in major cities is 4048 yuan/ton, up 39 yuan/ton from the previous trading day.

　　The editorial center of China Seamless Pipe Network was informed that steelmaking steel companies in most areas of the steelmaking industry are currently in a state of loss, and there are many enterprises that have stopped production and maintenance, and a few enterprises have begun to produce foundry steel to produce steel and steel. Although the steel market price fluctuated upwards, the steel mills' purchase of steelmaking steel was not high, steelmaking and steel transactions were not smooth, and the price rebounded weakly. It is expected that there will be no major fluctuations in the steelmaking steel market in the short term. Casting steel This week, the foundry steel market has a strong wait-and-see atmosphere, and transactions in some areas have improved.

　　The China Seamless Pipe Network website was informed that with the deepening of the supply side reform, the capacity to be effectively promoted, as a small variety downstream of the steel industry - seamless pipe is facing industry reshuffle. On the one hand, the profit level has increased in the past two years, and the newly added capacity is obvious. On the other hand, the elimination rate of SMEs in the industry is accelerating, and the new capacity increases the supply pressure of local billets. 　　

China's seamless pipe network has learned that the production efficiency and product quality of the rolling mills have obvious advantages, but the investment amount is large, and the pressure on private enterprises is relatively high. In 2018, Shandong Jinzhengyang put into operation a 180-rolling pipeline, and the Luli Group will kneel down. Jinsteel has put into operation two 159 units (a total of six, with a total capacity of 3 million tons). From the perspective of market response, the seamless pipes produced by the continuous rolling mills are more popular.

The products produced by our spiral steel pipe manufacturers often have waste products and finished products. We will not talk about these here. We directly enter the theme of today. We have made a technical update on the welding of the spiral steel pipe manufacturers. Too large directly causes a decrease in the proximity effect force, and also causes insufficient eddy current heat, and a bad crack is formed in the joint between the welds. This is a waste product.