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Valve sealing surface/inner leakage and deposited welding material

We all know that there are three major factors that affect valve life:

1 valve inner leakage: The main problem is the quality of the sealing surface
2 valve outside leakage: The main problem is the quality of the casting, but also packing problem
3 valve structure: The main problems in the design and processing of pieces

Here we discuss only the inner steel middle high pressure valve leakage problem, the requiement of valve sealing surfaces.

Valve sealing surface, at a predetermined pressure, temperature, medium, installation location,  ensure safe and reliable seal; while in the manufacturing process, the sealing surface materials and structures, welding, machining, assembly and grinding process shoudl be good; sealing surface should also to be ease of maintenance, specifically requires the following: Continue reading “Valve sealing surface/inner leakage and deposited welding material”

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China and main country Valve Welding material(electrode) for sealing surface

China Main Valve Sealing surfaceing Electrode Character,Use,Application 

D502 valve surfacing electrode line with GB EDCr-A1-03
Description: D502 is a titanium calcium type coating 1Cr13 valve welding electrode, AC and DC welding technology is good. Surfacing metal is 1Cr13 semi-ferritic chromium steel. Surfacing with air quenching properties, generally not subject to heat treatment, uniform hardness, but also softened by annealing at 750-800 ℃, when heated to 900-1000 ℃ air cooling or oil quenching, re-hardening.
Uses: This is a versatile surfacing welding rod for welding temperature below 450 ℃, carbon steel or alloy steel shafts and valves.
Chemical Composition of Deposited Metal (%) Chemical composition CSP Cr total of other elements
Guaranteed value ≤ 0.15 ≤ 0.030 ≤ 0.040 10.0 ~ 16.0 ≤ 2.50
Surfacing layer hardness: (after welding, air cooling) HRC ≥ 40
Reference current (AC, DC) electrode diameter (mm) φ2.5 φ3.2 φ4.0 φ5.0
Welding current (A) 50 ~ 80 80 ~ 120 120 ~ 160 160 ~ 200 Continue reading “China and main country Valve Welding material(electrode) for sealing surface”

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Thermoplastic materials as valve seat

A large number of thermoplastic materials are offered in valves, mainly as soft-seat  options for ball valve applications. Also lined valves like, lined butterlfy valve, lined globe valve, lined check valve. For this reason, the following section outlines some of the fundamental aspects of the properties, capabilities and application of these materials.

Material types
Mechanical properties
Chemical resistance

Material types

Table 1 shows the polymer types, used in valve applications, together with common abbreviations and Tradenames for the materials mentioned in these Guidelines. Continue reading “Thermoplastic materials as valve seat”