Some steel companies lowered the purchase price of scrap steel, ranging from 20-30 yuan (ton price, the same below). As a result, the scrap market from North China to East China has declined. At this stage, most traders did not participate. For the scrap market, the tradable resources of scrap steel are limited. Although the market price has been lowered, but the impact on the overall market is limited, and near the May Day holiday, individual steel companies have plans to replenish the scrap resources in advance. The overall downward adjustment of this scrap market is very limited. It is expected that the steel pipe scrap market will return to the consolidation trend in the near future, and the market will wait for the downstream industry to focus on the trend. The market in North China is stable and the Shanxi region is slightly adjusted. As the domestic mining market has been suppressed for a long time, in the case of a small rebound in billet prices, some mining companies in Tangshan and Shanxi last week tentatively raised the iron ore offer slightly, but did not receive the support of actual demand. The management companies are still controlling the purchases and waiting for the market price to fall. As a result, the iron ore market in North China is still dominated by the short-selling operation. It is expected that the market activity in North China will be limited in the later period, and the market is still difficult to improve. The market in Northeast China is in a state of consolidation. Most of the local large-scale mining companies mainly supply steel mills, and the transaction preferences. Small and medium-sized mining companies are not willing to trade at low prices, so the inventory has increased, close to the inventory ceiling. Merchants are looking forward to the improvement of the market after the "May 1st" holiday, they may ask the market after the holiday to think about shipping. It is expected that the market in Northeast China will remain stable in the near future, and the wait-and-see atmosphere will be strong. Today's market continues to be weak, and the transaction is general. It is understood that the market has only adjusted the purchase price of coke in individual steel mills. The steel mills in most regions have not adjusted the price. The main reason is that both the coke enterprises and the steel mills still have some objections to the price adjustment, so the original price is temporarily executed. According to Jiao Enterprise, coal inventories in steel mills in a few regions are generally maintained at around 5-7 days, which is basically close to the bottom line, and demand has always been sluggish. Comprehensive consideration, in the absence of good news in the late stage of the market, steel mills in order to profit or will continue to suppress the price of raw materials, it is expected that the domestic coke market will continue to be weak. Last week, the domestic steel market price under the impact of multiple negatives, the overall maintenance of the decline. Recently, the market's negative factors have been released, steel prices have plunged sharply, traders' confidence has been unstable, market transactions have been deserted, and steel prices have continued to fall.

Tubo soldado de acero inoxidable: se refiere a un tubo de acero con costuras en la superficie que se suelda en forma redonda o cuadrada con una tira de acero o placa de acero. De acuerdo con los diferentes métodos de soldadura, se puede dividir en tubería soldada con arco, tubería soldada con resistencia de alta o baja frecuencia, tubería soldada con gas, tubería soldada en horno, tubería Bondi, etc. Según la forma de la soldadura, se puede dividir en tubería soldada con costura recta y tubería soldada en espiral. Los tubos de acero soldados eléctricamente se utilizan en la perforación de petróleo y la fabricación de maquinaria. Los tubos soldados al horno se pueden utilizar como tubos de gas de agua, los tubos soldados longitudinalmente de gran diámetro se utilizan para el transporte de petróleo y gas a alta presión, etc .; los tubos soldados en espiral se utilizan para el transporte de petróleo y gas, pilotes de tuberías, pilares de puentes, etc. Los tubos de acero soldados tienen un costo más bajo y una mayor eficiencia de producción que los tubos de acero sin costura.


La tubería soldada de acero inoxidable tiene un proceso de producción simple, alta eficiencia de producción, bajo costo y rápido desarrollo. La resistencia de los tubos soldados de acero inoxidable es generalmente más alta que la de los tubos soldados con costura recta. Se puede utilizar un tocho más estrecho para producir tubos soldados con diámetros de tubería más grandes, y un tocho del mismo ancho se puede usar para producir tubos soldados con diferentes diámetros de tubo. Pero en comparación con la tubería de costura recta de la misma longitud, la longitud de la soldadura aumenta en un 30-100% y la velocidad de producción es menor. Por lo tanto, la mayoría de los tubos soldados de diámetro más pequeño adoptan soldadura de costura recta, y los tubos soldados de gran diámetro adoptan principalmente soldadura en espiral.


La fórmula de medición de la tubería soldada de acero inoxidable: fórmula de espesor de pared: δ = P * D / 2 * [σ]
Donde δ: unidad metro;
P: Unidad de presión de trabajo MPa;
[σ]: unidad de esfuerzo admisible MPa, [σ] = resistencia a la tracción / n, n es el factor de seguridad;
Cuando P <7MPa, n = 8; Cuando P <17.5MPa, n = 6;
Cuando P> 17,5 MPa, n = 4.