1. What Is a Stainless Steel Flanged Gate Valve?

A stainless steel flanged gate valve is one of the most widely used industrial valves designed for full shut-off or full opening of the flow. Made from 304 or 316 stainless steel, this valve offers exceptional resistance to corrosion, chemicals, high temperature, and high pressure, making it suitable for demanding and corrosive environments.

This type of valve is ideal for applications where the line must be either completely open or completely closed.
It is not suitable for flow regulation, as throttling may damage the internal components.

The flanged ends ensure safe installation, strong sealing, and secure connection in large industrial piping systems.

2. Difference Between 304 and 316 Stainless Steel

Both alloys are commonly used stainless steels in industrial piping.

Characteristics of Stainless Steel 304:

• Good corrosion resistance

• More economical

• Suitable for water, air, light steam, and non-corrosive fluids

Characteristics of Stainless Steel 316:

• Contains Molybdenum (Mo) → significantly enhanced corrosion resistance

• Suitable for seawater, acids, chlorides, and corrosive chemicals

• Better performance at high temperatures

Summary:

• 304 = economical, widely used

• 316 = premium choice for corrosive environments

3. Structure of Stainless Steel Flanged Gate Valve (304 | 316)

This valve is typically available as Wedge Gate or Knife Gate. Its main components include:

1. Body

• Material: Stainless steel 304 or 316

• Manufacturing: Cast or forged

• Ends: Dual flanges

• Standards:

  • ASME B16.5 (Class 150 / 300 / 600)

  • DIN PN16 / PN25

The body is designed to withstand operating pressure and high temperature.

2. Gate (Disc / Wedge)

The gate is the component that blocks or allows flow.

Types include:

• Solid Wedge

• Flexible Wedge

• Knife Gate (for slurry or viscous media)

Gate material is often 316 stainless steel for extended durability.

3. Bonnet

The bonnet encloses the upper part of the valve:

• Bolted Bonnet – most common

• Pressure Seal Bonnet – for very high pressure ratings

The bonnet houses the stem and must withstand line pressure.

4. Stem

The stem transfers motion from the handwheel or actuator to the gate.

Two types:

• Rising Stem → stem moves visibly

• Non-Rising Stem → ideal for limited installation space

Usually made from hardened stainless steel.

5. Seat

This is the sealing surface between the gate and the body.

Types:

• Metal-to-Metal Seat

• Soft Seat (NBR, EPDM, PTFE)

Metal seats are suitable for high temperature and steam applications.

6. Actuator / Handwheel

Gate valves can be operated through:

• Manual handwheel

• Gearbox

• Pneumatic actuator

• Electric actuator

• Hydraulic actuator

Selection depends on size, pressure, and fluid type.

4. How a Flanged Gate Valve Works

Gate valves operate in two modes:

Fully Open

The gate is fully lifted → minimal pressure drop.

Fully Closed

The gate is lowered → tight shut-off.

They are ideal for straight, high-pressure flow lines and not recommended for throttling, as this may cause:

• Vibration

• Seat damage

• Cavitation and turbulence

5. Advantages of Stainless Steel Flanged Gate Valves

✔ Excellent corrosion resistance (especially 316)

Ideal for chemicals, seawater, acids, and chlorides.

✔ Suitable for high temperature and high pressure

Commonly used in steam, hot oil, and gas lines.

✔ Very low pressure drop

The flow path is nearly straight when open.

✔ Long service life

Stainless steel ensures durability in tough environments.

✔ Compatible with a wide range of media

Water, gas, oil, steam, chemicals, alkaline solutions, and more.

✔ Strong and reliable flanged connection

Ensures vibration resistance and zero leakage.

6. Applications of Stainless Steel Flanged Gate Valve (304 | 316)

● Oil, Gas & Petrochemical Plants

Ideal for moderately corrosive chemicals and gases.

● Food, Pharmaceutical & Sanitary Industries

Stainless steel prevents contamination.

● Water Treatment & Desalination Systems

Perfect for seawater and industrial water.

● Marine & Offshore Industries

316 stainless steel is highly resistant to seawater corrosion.

● Steam & Thermal Systems

Handles high temperature and pressure effectively.

● Chemical Processing Plants

Suitable for weak to medium-strength acids and chemicals.

● Power Plants & Metal Industries

Used for hot oil and corrosive gas lines.

7. Key Factors When Buying a Stainless Steel Flanged Gate Valve

✔ Select the correct material (304 or 316)

Non-corrosive environment → 304
Corrosive / chemical → 316

✔ Check the flange class

• Class 150 → low/medium pressure

• Class 300/600 → high pressure

• Class 900+ → heavy-duty petrochemical service

✔ Choose the right gate type

• Solid Wedge → water & general service

• Knife Gate → slurry & viscous media

• Flexible Wedge → fluctuating pressure lines

✔ Select the correct stem type

Rising Stem offers higher reliability.

✔ Choose the right seat material

Metal Seat → steam / high temperature
Soft Seat → zero-leakage, sensitive fluids

8. Summary

The stainless steel flanged gate valve (304 | 316) is a powerful and durable industrial valve designed for full shut-off in high-pressure, high-temperature, and corrosive environments. With strong corrosion resistance, secure flanged connections, long lifespan, and compatibility with diverse media, it is an essential component in industries such as oil & gas, chemical processing, steam systems, water treatment, food, pharmaceuticals, and marine applications.