17-4PH valve stem

We can provide all kinds of valve stems, such as ball valve, gate valve, globe valve, etc., and can carry out grinding, electroplating and infiltration hardening treatment on the surface of the valve stem according to the needs of customers. The main materials are:

Duplex stainless steel	Forging grade	F51	F53	F55	F61
hastelloy	Forging grade	Inconel625	Inconel 600	Incoloy 825	Incoloy 926	Incoloy 800H	Incoloy 800
	Forging grade	Monel 400	Monel	S-Monel	Weldable Monel	Hastelloy C-276	Hastelloy C	Hastelloy C4
	Forging grade	Hastelloy C22	New Hastelloy C	Hastelloy B	Hastelloy B2	F904L	N3M
	Forging grade	Inconel718	Monel K-500	Inconel713	Nickel 200
austenitic stainless steel	Forging grade	F304	F316L	F316	F316LN	F347	F317	F317L
austenitic stainless steel	Forging grade	F310	F20	F62	F44
precipitation hardening stainless steel	Forging grade	17-4PH	15-5PH
carbon steel	Forging grade	410	A105	LF2	F6A
cobalt-base alloys	CO 3	CO 4	CO 6	CO 7	CO 12	CO 20	CO 21	CO 31
titanium alloy	ASTM B381	ASTM B367	ASTM B348	ASTM B265
copper alloy	ASTM B283	ASTM B148	ASTM B151	ASTM B584

Function of valve stem

The valve stem is the core transmission part of the valve, which mainly undertakes the following functions:

Power transmission: connect the handwheel and the electric/pneumatic actuator, transmit the operating torque through rotation or reciprocating motion, and control the opening and closing of the valve.
Sealing control: through the cooperation with the valve disc and stuffing box, ensure that the medium does not leak during the opening and closing process of the valve, especially bear the friction force and medium pressure of the packing seal.
Working condition tolerance: in direct contact with pipeline medium, it is necessary to resist the corrosion, high temperature and wear of the medium to ensure the long-term reliable operation of the valve.

Corrosion-resistant and high-temperature resistant alloy materials and their characteristics

1. Stainless steel series

material type	major constituent	Corrosion resistance characteristics	High temperature range	Typical application scenarios
304 stainless steel（0Cr18Ni9）	Cr≈18%，Ni≈9%	Resistant to atmosphere, water, weak acid and weak alkali corrosion, not resistant to chloride ion.	≤650℃	General chemical industry, water system, food industry
316 stainless steel（0Cr17Ni12Mo2）	Cr≈17%，Ni≈12%，Mo≈2%	After adding Mo, the corrosion resistance of chloride ion, sulfuric acid and seawater was significantly improved.	≤650℃	Seawater desalination, chemical chloride-containing media
Duplex stainless steel (such as 2205)	Cr≈22%，Ni≈5.5%，Mo≈3%，N≈0.15%	High strength+stress corrosion resistance, seawater and chloride corrosion resistance.	≤300℃ (strength decreases at high temperature)	Ocean engineering, petroleum refining, hydrometallurgy

2. hastelloy

material type	major constituent	Corrosion resistance characteristics	High temperature range	Typical application scenarios
Hastelloy C-276	Ni≈57%，Cr≈16%，Mo≈16%，W≈4%	Resistant to strong acids (such as sulfuric acid and hydrochloric acid), high temperature and high pressure corrosion, and resistant to chloride ion stress corrosion.	≤1200℃	Chemical concentrated acid, flue gas desulfurization and seawater heat exchanger
Monel alloy (Monel 400)	Ni≈67%，Cu≈30%	Corrosion resistance to hydrofluoric acid, fluoride, seawater and neutral salt solution.	≤480℃	Hydrofluoric acid processing, marine seawater system
Inconel 625（Inconel 625）	Ni≈61%，Cr≈21%，Mo≈9%，Nb≈3.6%	Oxidation resistance, corrosion resistance (such as chloride and seawater), and excellent high-temperature strength.	≤1093℃	Aerospace, high temperature corrosive environment (such as gas turbine)

3. Titanium and titanium alloys

material type	major constituent	Corrosion resistance characteristics	High temperature range	Typical application scenarios
Industrial pure titanium (TA2)	Ti≥99%	Resistant to seawater, chlor-alkali and wet chlorine, not resistant to high temperature oxidation.	≤300℃	Chlor-alkali industry, seawater desalination, ship valves
Titanium alloy (such as Ti-6Al-4V)	Ti+Al+V	High strength+corrosion resistance, seawater and chloride stress corrosion resistance.	≤400℃	Ocean engineering, high-pressure corrosion-resistant valves

4. Cobalt-based alloy (Stellite)

Composition: Co≈50%, Cr≈25%, W≈5-15%, containing C, Ni, etc.
Characteristics: high temperature wear resistance, corrosion resistance (such as high temperature sulfide), temperature resistance up to 1100℃, but high cost.
Application: high temperature and high pressure medium containing solid particles (such as steam valve of power plant and valve of garbage incinerator).

Analysis of application differences of different materials

1. Choose according to the corrosiveness of the medium.

Weakly corrosive environment (such as water, atmosphere and dilute acid): 304/316 stainless steel is preferred, with low cost and satisfactory performance.
Strong corrosive environment:
- Containing chloride ion (such as seawater and hydrochloric acid): choose 316L, duplex stainless steel or Hastelloy C-276.
- Hydrofluoric acid: Only Monel alloy (Ni-Cu alloy) can be used, and other materials are easy to corrode.
- Concentrated nitric acid and concentrated sulfuric acid: Hastelloy C-276 or titanium alloy (titanium is passivated in concentrated nitric acid).

2. Select according to temperature requirements

Medium and low temperature (≤ 650℃): 304/316 stainless steel, duplex stainless steel.
High temperature (650-1000℃): Inconel 625, Hastelloy C-276, which need to give consideration to oxidation resistance.
Ultra-high temperature (> 1000℃): Stellite cobalt-based alloy, which is resistant to high temperature oxidation and wear.

3. Select according to the special requirements of working conditions

High pressure+corrosion: duplex stainless steel (high strength) or titanium alloy (stress corrosion resistance).
Serious wear: Stellite alloy (high surface hardness, erosion resistance).
Food/pharmaceutical industry: 316L stainless steel (nontoxic and easy to clean).

summary

The selection of valve stem material needs to integrate media characteristics (composition and concentration), temperature, pressure and cost factors. Stainless steel is the most commonly used basic material. Nickel-based alloys and titanium alloys are suitable for harsh working conditions, while cobalt-based alloys are suitable for high-temperature wear scenarios. In practical application, it is necessary to verify the compatibility of materials through corrosion tests (such as intergranular corrosion test and salt spray test) to ensure the long-term reliable operation of the valve.

Function of valve stem

Corrosion-resistant and high-temperature resistant alloy materials and their characteristics

1. Stainless steel series

2. hastelloy

3. Titanium and titanium alloys

4. Cobalt-based alloy (Stellite)

Analysis of application differences of different materials

1. Choose according to the corrosiveness of the medium.

2. Select according to temperature requirements

3. Select according to the special requirements of working conditions

summary

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