Hydraulic Valves Material Inventory Of Valve Body

At present, most of the hydraulic valve varieties are ductile iron as the main valve body material.

The material of the main parts of the valve body of the hydraulic valve should be first taken into account the physical properties (temperature, pressure) and chemical properties (corrosivity) of the working medium.

At the same time, we should also understand the cleanliness of the medium (there is no solid particles). In addition, reference to the relevant provisions and requirements of the State and the use sector.

Hydraulic valve body material, a wide variety, applicable to a variety of different working conditions. The commonly used shell materials, internal materials and sealing surface materials are described below.

Hydraulic valve body commonly used material

1. Iron

Gray iron valve is used in various fields of industry for its low price and wide application. They are commonly used in the case of water, steam, oil and gas, and are widely used in chemical, printing and dyeing, oil, textile and many other industrial products that have little or no impact on iron pollution.

Suitable for working temperature between –15~200℃, nominal pressure pn≤1.6MPa low pressure hydraulic valve body.

2. Black-hearted malleable cast iron

Suitable for working temperature between –15~300℃, nominal pressure pn≤2.5MPa medium and low pressure hydraulic valve body. Applicable medium for water, seawater, gas, ammonia and so on.

3. Iron

Ductile iron is a kind of cast iron, this cast iron, pellet or spherical graphite replaces the flake graphite in gray iron. This change in the internal structure of the metal makes its mechanical properties better than that of ordinary gray cast iron and does not damage other properties. Therefore, the hydraulic valve body made of ductile iron is more pressure than that of the hydraulic valve body made of gray iron. Suitable for working temperature between –30~350℃, nominal pressure pn≤4.0MPa medium and low pressure hydraulic valve body.

Applicable medium for water, seawater, steam, air, gas, oil and so on.

4. Carbon

(WCA, WCB, WCC) at first the development of cast steel was to accommodate those beyond the cast iron valves and bronze valve capabilities of production needs. However, because of the good performance of the carbon steel valve, and the resistance strength of the stress caused by the thermal expansion, the impact load and the pipeline deformation, the use range is enlarged, which usually includes the working condition of the cast iron valve and the bronze hydraulic valve body.

Suitable for working temperature in the middle and high pressure hydraulic valve body between –29~425℃. Among them 16Mn, 30Mn temperature is –40~400℃, commonly used to replace the ASTM A105. The applicable medium is saturated steam and superheated steam. High temperature and low temperature oil, liquefied gas, compressed air, water, gas and so on.

5. Low Temperature carbon steel

(LCB) Low-temperature carbon steel and low nickel alloy steel can be used for temperatures below zero, but not extended to deep cold areas. The hydraulic valve body made of these materials is suitable for the following media, such as seawater, carbon dioxide, acetylene, propylene and ethylene.

Suitable for operating temperature in the –46~345℃ between the low-temperature hydraulic valve valve body.

6. Steel

HYDRAULIC Valve Bodies (WC6, WC9) Low-alloy steels, such as carbon molybdenum steel and CR-Mo Steel, can be applied to a wide range of working mediums, including saturated and superheated steam, cold and hot oil, gas and air. Carbon steel valve operating temperature can be used to 500 ℃, low alloy steel valves available to 600 ℃ or more. At elevated temperatures, the mechanical properties of low-alloy steels are higher than those of carbon steel.

High-temperature high-pressure hydraulic valve body which is suitable for working temperature between –29~595℃ and non corrosive medium; C5, C12 is suitable for high-temperature high-pressure hydraulic valve body of corrosive medium between –29~650℃ and operating temperature.

7. Austenitic stainless Steel

Austenitic stainless steel contains about 18% chromium and 8% nickel. 18-8 austenitic stainless steel is often used as a hydraulic valve body and bonnet material under high and low temperatures and strong corrosion conditions. Adding molybdenum to 18-8 stainless steel matrix and slightly increasing the content of nickel can substantially increase its corrosion resistance. Hydraulic valve body made of this kind of steel can be used extensively in chemical industry, such as transporting acetic acid, nitric acid, alkali, bleach, food, juice, carbonic acid, tanning liquid and many other chemical products.

In order to apply the high temperature range, further change the material composition, in this stainless steel to add niobium, is known as the 18-10-NB, the temperature can be used to 800 ℃.

Austenitic stainless steels are usually used at very low temperatures and do not become brittle, so the hydraulic valve body made of this material (such as 18-8 and 18-10-3MO) is suitable for working at low temperatures. For example, the transport of liquid gases, such as natural gas, biogas, oxygen and nitrogen.

The hydraulic valve body is suitable for the corrosive medium between –196~600℃ and working temperature. Austenitic stainless steel is also ideal for cryogenic hydraulic valve body material.

8. Monel Alloy

' Monel ' is a high nickel-copper alloy with good corrosion resistance. This material is often used in the transportation of alkali, salt solution, food and many gas-free acid hydraulic valve body, especially sulfuric acid and hydrofluoric acid. ' Monel ' alloys are ideal for steam, seawater and marine environments. It is mainly suitable for the hydraulic valve body containing fluorine chlorate medium.

9. Ha Alloy

Mainly applicable to dilute sulfuric acid and other strong corrosive medium hydraulic valve body.

(1) ' Ha ' alloy b

The alloy contains 60% nickel, 30% molybdenum and 5% iron. It is particularly resistant to the strong corrosion of inorganic acids, ' ha ' alloy ' B ' for various concentrations of hydrochloric acid can be used to the boiling point temperature, and for sulfuric acid, in the most corrosive concentrations can be used to 70 ℃. For phosphoric acid, it can be used under various conditions, and ' ha ' alloy ' B ' is also suitable for ammonium chloride, zinc chloride, aluminum sulfate and ammonium sulfate.

In an oxidizing atmosphere, ' ha ' alloy ' B ' can be used to approximately 800 ℃, and in a reduction atmosphere, the temperature can be higher.

(2) ' Ha ' alloy C

This alloy is a nickel base alloy containing 15% chromium and 17% molybdenum. In both oxidation and reduction atmospheres, it can be used for 1100 ℃. It has good corrosion resistance to hydrochloric acid, sulfuric acid and phosphoric acid. And in many cases, it can also be used for nitric acid.

' Ha ' alloy ' C ' has strong corrosion resistance to chlorides, chlorides, sulfides, oxidizing salts and many other corrosive mediums. It is also especially suitable for halogen-like media, such as hydrofluoric acid.

$number. Titanium

Mainly applicable to all kinds of strong corrosive medium hydraulic valve body.

$number. Cast Copper alloy

Industrial hydraulic valve Body Many are made of non-ferrous materials, mainly bronze and brass. The proportion of copper, tin, lead, and zinc in the bronze alloy that manufactures the valve body of the hydraulic valve is usually 85:5:5:5 or 87:7:3:3. If zinc-free bronze is required, it must be explained. The physical strength, structural stability and corrosion resistance of bronze make it especially suitable for industrial production. Industrial Bronze hydraulic valve body diameter up to 100mm.

Bronze valves are commonly used at relatively moderate temperatures, with some grades of bronze available to around 280 ℃. In the low temperature, most copper alloys have the characteristics of being brittle at very low temperatures, which makes the bronze widely used under low temperature conditions, such as liquid oxygen and liquid nitrogen, whose temperature is below 180 ℃.

$number. No. 20th Alloy

In ordinary stainless steel is not competent to very strict circumstances, the most interested in a class of steel is high alloy stainless steel. Perhaps the most common type of alloy steel is no. 20th. It contains 29% nickel, 20% chromium, plus molybdenum and copper. This alloy has strong resistance to various temperatures and concentrations of sulfuric acid. In addition, in most cases, it can also be used in phosphoric acid and acetic acid media, especially in cases where chlorides and other impurities are available.

$number. Two-way stainless steel

The development trend of bidirectional stainless steel (ferrite structure or austenite structure). This steel contains 20% or more chromium and 5% of nickel, as well as a certain amount of molybdenum, the strength and hardness of these alloys than ordinary austenitic stainless steel, and in sulfuric acid and phosphoric acid in very poor conditions, the ability to resist local corrosion is very strong.

It is mainly applied to the hydraulic valve body of the working temperature between the –273~200℃ oxygen pipe and seawater pipeline.

$number. Plastics, Ceramics

Both of these materials are non-metallic. Non-metallic material hydraulic valve body's biggest characteristic is the corrosion resistance is strong, even has the metal material hydraulic valve body not to have the advantage. Generally applies to the nominal pressure pn≤1.6MPa, the working temperature is not more than 60 ℃ corrosive medium, non-toxic plastic hydraulic valve body also applies in the water supply industry. Plastic, ceramic hydraulic valve body generally can not be used as a hydraulic valve body material, the need for steel material skeleton, lined with plastic, ceramic.