The finishing process of large-diameter flat welding flanges is a complex and meticulous procedure, mainly including the following key steps:

I. Raw Material Preparation

● Material selection: High-quality thick steel plates are chosen as raw materials. Materials with good mechanical properties and corrosion resistance, such as carbon steel, stainless steel or alloy steel, are usually selected.

● Inspection: Conduct strict inspections on raw materials, including non-destructive testing methods such as ultrasonic flaw detection, to ensure that the raw materials have no defects such as delamination and slag inclusion.

Ii. Preliminary Processing

● Cutting: According to the size requirements of the flange, high-precision cutting equipment is used to cut the raw materials to obtain the flange blank that meets the requirements.

● Pretreatment: Pre-treat the flange blanks after cutting, such as deburring and rust removal, to enhance the quality and efficiency of subsequent processing.

Iii. Forming Processing

● Forging: The flange blank is forged to increase its density and strength. During the forging process, it is necessary to control the forging force and temperature to ensure that the shape and size of the flange meet the design requirements.

● Mechanical processing: Use mechanical processing equipment such as lathes and milling machines to further process the flange, such as turning and milling, to achieve the required precision and surface quality.

Iv. Welding and Inspection

● Welding: Weld the flange to the pipe or other connecting parts. Before welding, the welding surface needs to be cleaned and pre-treated to ensure the welding quality. During the welding process, it is necessary to control welding parameters such as welding current, voltage and speed to avoid the occurrence of welding defects.

● Inspection: Quality inspection is carried out on the flanges after welding, including visual inspection of the weld seams, non-destructive testing (such as X-ray testing, ultrasonic testing, etc.) and mechanical property testing, etc., to ensure that the welding quality meets relevant standards and requirements.

V. Surface Treatment and Finishing

● Surface treatment: Necessary surface treatments such as sandblasting, shot blasting, painting or anti-rust treatment should be carried out on the flange to enhance its corrosion resistance and aesthetic appeal.

● Finishing: Perform final finishing on the flange, such as polishing and grinding, to achieve the required surface roughness and gloss. During the fine processing, high-precision processing equipment and tools are required to ensure the dimensional and shape accuracy of the flange.

Vi. Inspection and Packaging

● Inspection: Conduct a comprehensive inspection of the finely processed flanges, including dimensional inspection, shape inspection, surface quality inspection, etc., to ensure that they meet the design requirements and relevant standards.

● Packaging: The flanges that have passed the inspection are packaged to prevent damage during transportation and storage. The packaging materials should be moisture-proof, rust-proof and corrosion-proof, and the model, specification, quantity and other information of the flange should be indicated.

In conclusion, the precision processing flow of large-diameter flat welding flanges is a complex process involving multiple links and various processing techniques. Through strict raw material inspection, preliminary processing, forming processing, welding and testing, surface treatment and fine processing, as well as inspection and packaging, the quality and performance of flanges can be ensured to meet relevant standards and requirements.