2022-05-07
ACME Corporation of the United States visited our company for an inspection.
On April 28, 2016, Mr. Jack Goldberg, Chairman of METALS & STEEL SUPPLY INCORPORATED (ACME) of the United States, accompanied by Mr. Yang Haiyang, Vice President of Huamin Group, paid a visit to our company for an inspection and fact-finding tour.
2022-05-07
What is the difference between welded steel pipe and welded spiral steel pipe?
Welded steel pipe refers to steel pipe with a welded seam, manufactured by bending steel strip or steel plate into circular, square, or other cross-sectional shapes and then welding them together. The raw material used for welded steel pipe is either steel plate or steel strip. Since the 1930s, driven by the rapid development of continuous strip‑rolling production and advances in welding and inspection technologies, weld quality has steadily improved, leading to an expanding range of grades and specifications. As a result, welded steel pipe has increasingly replaced seamless steel pipe in a growing number of applications. Compared with seamless steel pipe, welded steel pipe offers lower costs and higher production efficiency.
Reassessing the Issue of Long Welds in Spiral Steel Pipes
For a long time, there has been ongoing debate over whether spiral‑welded pipe or straight‑seam pipe—particularly in comparison with UOE‑type pipe—is superior. As spiral‑welded pipe manufacturing technology has advanced to its present state, we should conduct a proper evaluation and comparison, and reassess the issue of the relatively longer weld seams in spiral‑welded pipes. First,
07
2022/05
Definition and Explanation of Steel Plate Bow in Spiral Welded Pipe Mills
Definition and Explanation of Steel Plate Crown in Spiral Steel Pipe Factories: Acn — thickness measured by the center‑line thickness gauge; hm — thickness measured by the gauge located 40 mm from the edge on the drive side; hos — thickness measured by the gauge located 40 mm from the edge on the operating side. In actual rolling processes, plate crown may develop a wedge‑shaped profile. Generally, when the crown exceeds 40 µm, Wq should be less than; when the crown is less than 20 µm, Wq should be less than 27 µm. What is the mechanism behind the formation of steel plate crown? During rolling, the crown of the strip depends on the roll crown under load, the initial crown of the metal sheet, and the shape of the mill’s roll gap, which ultimately determines the strip’s final profile. The factors involved include: - Roll crown under no load; - Original roll geometry; - Roll crown in the hot state; - Roll wear; - Load‑induced roll crown. These elements collectively determine the roll gap configuration and constitute the primary control variables in the mathematical model. By specifying the original roll setting and adjusting bending rolls and tandem rolls, it is possible to modify both crown and flatness, ensuring that the elongation at the edges and in the center of the strip remains consistent, thereby achieving an ideal profile. For hot‑rolled sheets, there are generally no explicit tolerance specifications for crown control; the main objective is to meet the requirements of subsequent cold‑rolling operations. Cold‑rolling imposes a stricter tolerance on the crown of the incoming hot‑rolled sheet, typically requiring it to be less than 0.007 mm. In spiral steel pipe factories, “plate shape” refers to the uniformity of thickness distribution across the transverse cross‑section of the steel plate and the overall flatness of its surface. It is commonly believed that poor plate shape arises from uneven longitudinal elongation along the width direction. More precisely, plate shape is caused by residual stresses remaining in the strip after rolling. Specifically, the workpiece emerging from the roll gap may still retain relatively free ends, allowing variations in width‑wise deformation to manifest visibly at the leading edge. However, as the material continues to pass through the mill, these non‑uniform elongations become constrained, and their effects no longer appear clearly at the front end. Consequently, residual stresses—primarily tensile stresses acting longitudinally across the width—develop during the rolling process. When these residual stresses reach a sufficient magnitude, they give rise to defects such as waviness or warping.
07
2022/05
In recent years, emerging industries such as the internet and the virtual economy have grown rapidly, becoming sunrise industries, while traditional sectors like spiral steel pipe have come to be viewed as sunset industries.
07
2022/05