Thermal treatment technique for improving rigidity of integer manhole flange sealing surface

Abstract

The invention relates to a heat treatment process for improving the hardness of the sealing surface of an integral manhole flange. The process includes blanking, manufacturing of flanges and flange jackets, assembly, welding, finishing and hydraulic testing. In the assembly process, the outer edge of the joint surface of the flange and the flange jacket The welding groove is machined by turning, the angle of the groove is 35°~55°, and the thickness of the blunt edge of the groove shall not exceed 1mm; in the welding process, sub-arc welding is used to make the bottom and manual arc welding is used to cover the surface. The present invention ensures that the welding can be penetrated through the control of the groove angle, the process parameters of the blunt edge thickness of the groove and the welding method, ensures the welding quality of the weld seam, and overcomes the easy leakage of the flange and the flange jacket The deficiency prolongs the service life of the product.

Description

technical field [0001] The invention relates to a flange processing technology, in particular to a heat treatment technology for improving the hardness of the flange sealing surface of an integral manhole. Background technique [0002] Integral manhole flanges are generally used on high-pressure vessels, such as hydrogenation reactors, coking towers, etc., and their materials are generally 15CrMo. In the design, the sealing surface of the flange adopts the annular connection surface, and the sealing material generally adopts 0Cr13 octagonal pad or oval pad. The flange must be heat treated by normalizing + tempering, and the hardness of the sealing surface is required to be 30HB greater than that of the gasket. [0003] At present, people generally adopt the method of flame heating and quenching or chrome plating on the sealing surface to improve the hardness of the flange sealing surface. But these two methods have the following disadvantages: [0004] 1. Disadvantages of...

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Problems solved by technology

[0004] 1. Disadvantages of chrome plating on the surface: during the fastening process, the chrome layer is easy to fall off due to extrusion, resulting in leakage at the position where the chrome layer falls off during use

[0005] 2. Disadvantages of flame heating and quenching: using flame heating to partially heat and quench the sealing surface is an economical and practical method, but at the beginning and end of flame heating, it is difficult to ensure that its hardness is the same as other positions

As a result, leakage is prone to occur at this position during use

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