Use of welding materials and gaskets for valve maintenance

Use of welding materials and gaskets for valve maintenance

Welding is mainly used for surfacing of valve sealing surface, repair welding of casting defects and welding of product structure. The selection of welding materials is related to the process method, manual arc welding, plasma spray welding, submerged arc automatic welding, carbon dioxide gas shielded welding, the materials used are different. Here we only introduce the most commonly used welding method – manual arc welding used in various materials. Sealing surface surfacing materials have been introduced in the second section of the inner material, this chapter focuses on the casting repair welding, manual arc welding for structural welding of various electrodes.
Welding material
Welding is mainly used for surfacing of valve sealing surface, repair welding of casting defects and welding of product structure. The selection of welding materials is related to the process method, manual arc welding, plasma spray welding, submerged arc automatic welding, carbon dioxide gas shielded welding, the materials used are different. Here we only introduce the most commonly used welding method – manual arc welding used in various materials. Sealing surface surfacing materials have been introduced in the second section of the inner material, this chapter focuses on the casting repair welding, manual arc welding for structural welding of various electrodes.
1 Requirements for welders
Welders shall pass the basic knowledge and operation examination of the Boiler and Pressure Vessel Welder Examination Rules formulated by the Ministry of Labor and Personnel of the People’s Republic of China, and hold the qualification certificate before engaging in welding operations within the validity period.
Valve belongs to pressure vessel, welder’s technical level and welding process directly affect product quality and safety production, so it is very important to strict requirements for welders, welding is a special process in valve production enterprises, special process must have special means, including personnel, equipment, material management and control.
2 Storage requirements for welding rods
(1) Pay attention to the environmental humidity to prevent the electrode from moisture, the relative humidity in the air is less than 60%, and leave the ground and the wall a certain distance (about 30cm).
(2) to distinguish electrode type, specifications can not be confused.
(3) Transportation stacking process should be careful not to damage the drug skin, especially for stainless steel electrode, cast iron electrode, etc.
Welding rod commonly used for casting repair welding and structural welding of valve products
Refer to Table 1-3-1 for welding rod grades commonly used in casting repair welding and structural welding of valve products.
Table 1-3-1 Common welding rod grades
category
brand
model
AWS
standard
Carbon steel welding rod
J422
J502
E4303
E5003
GB/T 5117
J507
*CHE508-1
E5015
E5018-1
E7015
E7018-1
Stainless steel electrode
R507
A102
A132
A002
A202
A212
A022
A302
A402
Chromium 202
E1-5MoV-15
E0-19-10-16
E0-19-10Nb-16
E00-19-10-16
E0-18-12Mo2-16
E0-18-12MoNb-16
E00-18-12Mo2-16
E1-23-13-16
E2-26-21-16
E1-13-16
E502-15
E308-16
E347-16
E308L-16
E316-16
E318-16
E316L-16
E309-16
E310-16
E410-16
GB/T 983
Cont. 1-3-1 Common welding rod grades
Low alloy heat resistant steel electrode
R337
E5515-B2-VNb
R107
R307
R407
E5015-A1
E5515-B2
E6015-B3
E7015-A1
E8015-B2
E9015-B3
GB/T 5118
Low bonding steel electrode
707 wen ni
E5515-C1
GB/T 5118
907 wen ni
E5515-C2
E8015-C2
107 wen ni
E7015-G
Monel electrode
R-M3NiCu7
ERNiCu-7
Stainless steel wire
H0Cr20Ni10Ti
H0Cr21Ni10
H0Cr19Ni12Mo2
H00Cr21Ni10
H00Cr19Ni12Mo2
GB/T 4241
* CHE 508-1 is equivalent to Chinese electrode factory brand GB E5018-1.
1, 2, 3, 4, 1, long stored valve valve maintenance, regular check should be done, for the leakage of the processing surface should be clean, * * * dirt, storage and ends when the ball valve should be blocked in an open position, gate valve, globe valve, check valve, the ends of the channel should be blocked and closed, neatly stored in indoor and ventilated dry place, Stacking or open storage is strictly prohibited.
2, before installation, it is necessary to carefully check the pressure of the valve mark, whether the diameter meets the requirements, eliminate the defects caused by the transportation process, and eliminate the dirt of the valve parts.
3. When installing, the valve can be directly installed on the pipeline according to the connection mode. In general, it can be installed in any position of the pipeline, but it needs to be easy to operate and repair. Note that the flow direction of the globe valve medium should be upward from the bottom of the vertical disc, and the lifting check valve can only be installed horizontally.
4, ball valve, globe valve, gate valve, only for full open or full closed, not allowed to adjust the flow, so as to avoid erosion sealing surface, accelerate wear. There is an inverted sealing device in the gate valve and the upper thread globe valve, and the handwheel is tightened to the top position of ** to prevent the media from leaking from the packing.
5, ball valve, globe valve, gate valve open and close the application of handwheel, do not use levers or other tools, so as not to damage the valve. If the handwheel rotates clockwise, it is closed, otherwise, it is open.
6, packing gland bolts should be tightened evenly, should not be pressed into a crooked state, so as not to interfere with the stem movement or cause leakage.
7, the valve in the process of use, should always keep clean, drive thread must be regularly lubricated, found fault, should immediately stop using, find out the cause of failure.