Ministry of Chemical Industry Standard

Ministry of Chemical Industry Standard

This article analyzes in detail the difference between the national standard of the valve and the standard of the Ministry of Chemical Industry, mainly the difference between the flanges.

In China’s valve classification, there are mainly GB flanges of national standard, HG standard flanges of the Ministry of Chemical Industry, and JB standard flanges of the Ministry of Machinery.

Not only Chinese domestic valves have these flange standards, but some foreign valves also launch these flanges for the Chinese market.

Flange standard valves, such as VTON VTON in the United States, mainly include GB flanges of national standard, HG standard flanges of the Ministry of Chemical Industry, imported ball valves of JB standard flanges of the Ministry of Machinery, imported globe valves, imported gate valves, imported butterfly valves, and imported check valves. Wait, let’s analyze the standards and differences of these flanges.

GB standards are the Chinese national standards issued by the Standardization Administration of China

(SAC), are applied nationally throughout China and define the requirements relating to product safety and quality.

Chinese national standards are often harmonized with, or have been developed based on, ISO, IEC or other international standards.

1. National standard GB flange marking is done according to:

• Flange
• Nominal diameter
• Nominal pressure (nominal pressure value is 10 times Mpa)
• Sealing surface shape code
• Corresponding steel pipe series code (corresponding inch pipe is not marked, corresponding metric system The code is “Series 2”)
• Standard number is marked sequentially

MARKUP EXAMPLES

o Nominal diameter 125mm, nominal pressure 4.0MPa flat welding flange with raised face and neck (with metric pipe)

჻ Flange DN125－PN40 RF (Series 2) GB/T9116.1－2000

o Ring connection face welding flange with nominal diameter of 65mm and nominal pressure of 11.0MPa (with inch pipe)

჻ Flange DN65-PN110 RJ GB/T9115.4-2000, such as the national standard flanged globe valve of Weidun VTON.

2.HG flange marking of the Ministry of Chemical Industry

MARKUP EXAMPLES

o Nominal diameter 300mm, nominal pressure 4.0MPa, concave necked flat welding flange, equipped with inch pipe, material is A105

჻ HG20592-1997 Flange SO300 (A)-4.0 FM A105

჻ HG20592-2009 Flange SO300 (A)-40 FM A105

o Nominal diameter 600mm, nominal pressure 1.0MPa, full flat flange cover, equipped with metric pipe, material is stainless steel flange 304

჻ HG20592-1997 Flange BL600 (B)-1.0 FF 304

჻ HG20592-2009 Flange BL600 (B)-10 FF 304

o The nominal diameter is 300mm, the nominal pressure is 1.6MPa, the raised face flat welding ring loose flange, is equipped with an inch pipe, the steel pipe wall thickness is 5mm, the material is: flange 304, flat welding ring 316

჻ HG20592-1997 Flange PJ/RJ 300(A)－1.6 RF S=5mm 304/316

჻ HG20592-2009 Flange PJ/RJ 300（

A）－16 RF S＝5mm 304/316o The nominal diameter is 125mm, the nominal pressure is 6.3MPa, the butt welding flange with raised face and neck is equipped with metric pipe, the wall thickness of the steel pipe is 11mm, and the material is stainless steel flange 316

჻ HG20592-1997 Flange WN125（

B）－6.3 M S＝11mm 316

჻ HG20592-2009 Flange WN125(B)－63 M S=11mm 316, such as Weidun VTON Chemical Flange Ball Valve.

3.JB flange mark of the mechanical department

According to flange, nominal diameter DN, nominal pressure PN, sealing surface form code, flange outer diameter size code (default flange outer diameter is small outer diameter series 2 – not marked, large outer diameter series is “series 1”) and standard number sequence markers.

NOTE: Flange sealing surface classification: A-type convex surface, B-type concave surface, C-type tenon surface, D-type groove surface.

The nominal pressure value is 10 times Mpa.

MARKUP EXAMPLES

o Nominal diameter 500mm, nominal pressure 4.0MPa, flange outer diameter is series 2 raised face welding flange

჻ Flange 500-40A JB/T82.2-1994

o Nominal diameter 500mm, nominal pressure 1.6MPa, flange outer diameter is series 1 convex surface (raised surface) flat welding flange cover

჻ Flange cover 500-16 (Series 1) JB/T86.1-1994

o Nominal diameter 300mm, nominal pressure 0.6MPa, flange outer diameter is series 1 flanging plate loose flange

჻ Flange 300-6 (Series 1) JB/T85-1994

჻ Stainless steel flange /fla

჻ Flat welding flange /flb

჻ Butt welding flange /flc

჻ Flange cover /fli