High Performance Carbon Steel / Stainless Steel Bolted Bonnet OS&Y Type Gate Valve Class 150, 300 and 600

Mayur (Valves) System Private Limited is a trusted manufacturer of high-performance bolted bonnet OS&Y type gate valves — focused on delivering precision-engineered carbon steel, stainless steel, super duplex, alloy 20, and ductile iron gate valves designed for demanding industrial service across oil and gas, refinery, chemical, power, and process applications.

In serious industrial pipelines, the gate valve is one of the most relied-upon components for full-bore isolation. When the line is running, the valve must allow uninterrupted flow with minimal pressure drop. When the line needs to be shut, the valve must close completely, hold tight, and stay reliable for years. There is very little room for compromise — especially in high-pressure, high-temperature, and corrosive service.

This is exactly why bolted bonnet OS&Y (Outside Screw and Yoke) type gate valves have become the global standard for heavy industrial duty. Their robust construction, clear position indication, and strong sealing performance make them the preferred choice in refineries, chemical plants, and power facilities. At Mayur (Valves) System Private Limited, we manufacture bolted bonnet OS&Y gate valves engineered to international standards including API 600, API 603, and API 598 — built for serious, project-grade industrial use.

What Is a Bolted Bonnet OS&Y Type Gate Valve

A bolted bonnet OS&Y type gate valve is a full-bore isolation valve where the bonnet is bolted firmly to the body, and the stem rises through an outside screw and yoke (OS&Y) arrangement. This design offers some of the strongest mechanical integrity and the clearest visual indication of valve position in the industry.

In simple terms:

• The bolted bonnet delivers strong, leak-tight body-to-bonnet sealing under high pressure
• The OS&Y design keeps the stem threads outside the fluid path, protecting them from corrosion and wear
• The visible rising stem clearly indicates whether the valve is open or closed
• The flexible wedge gate supports leak-tight shut-off across varying temperatures

This is exactly why Flexible Wedge Outside Screw and Yoke Bolted Bonnet API 600 Gate Valves are widely used across the oil and gas, refining, and chemical industries worldwide.

Class 150, Class 300, and Class 600 Pressure Ratings

We manufacture bolted bonnet OS&Y gate valves in Class 150, Class 300, and Class 600 pressure ratings, giving plant teams the flexibility to match the valve to the exact service condition of every line.

• Class 150 — ideal for moderate-pressure utility and process lines
• Class 300 — for higher-pressure industrial duty across chemical and refinery applications
• Class 600 — for high-pressure service in oil and gas, power, and demanding process plants

All our valves are designed, manufactured, and tested in line with internationally recognised standards such as API 600, API 603, and API 598 — supporting consistent dimensional accuracy, pressure rating compliance, and quality assurance for global projects.

Available Materials and Configurations

A serious industrial gate valve is defined as much by its body material as by its design. We manufacture our bolted bonnet OS&Y gate valves in a wide range of body materials and configurations to suit every duty.

Standard offerings include:

• Stainless Steel Gate Valve in CF8 and CF8M grades
• API 603 Corrosion Resistant Stainless Steel Gate Valve for chemical duty
• API 600 Stainless Steel Gate Valve Flanged Ends Class 300 for high-pressure service
• API 603 150# CF8M Stainless Steel OS&Y Gate Valve for general corrosive applications
• API 603 Stainless Steel Corrosion-Resistant Gate Valves across multiple classes
• Super Duplex F53 F55 5A 6A Gate Valves Flanged Ends for aggressive offshore and chemical service
• ASTM A 351 GR. CN7M Alloy 20 Bolted Bonnet Rising Stem Gate Valves for sulphuric acid handling
• API 600 Cast Carbon Steel Gate Valve Flanged Ends Class 150 for standard industrial duty
• Ductile Iron Flanged Gate Valve Bronze Trim Class 150
• Ductile Iron Flanged Gate Valve Stainless Steel Trim Class 150
• Ductile Iron Flanged Gate Valve Aluminium Bronze Trim Class 150

This breadth of options gives EPC contractors, project consultants, and plant teams full flexibility to specify the right material grade, trim configuration, and pressure rating for every line.

Key Features of Mayur Bolted Bonnet OS&Y Gate Valves

Our gate valves are engineered around features that genuinely matter in heavy industrial duty:

• Strong bolted bonnet construction for high-pressure integrity
• OS&Y design with clear visible position indication
• Flexible wedge gate for reliable, leak-tight shut-off across temperature variations
• Full-bore flow path for minimal pressure drop
• Compliance with API 600, API 603, and API 598 standards
• Flanged end connections matching global piping specifications
• Compatible with manual handwheel, gear box, and actuator operation
• Strong corrosion resistance across stainless steel, super duplex, and alloy 20 grades
• Long service life with simple maintenance

Common Industrial Applications

Our bolted bonnet OS&Y gate valves are trusted across a wide range of demanding industries, including:

• Oil and gas exploration, production, and refining
• Petrochemical and chemical processing plants
• Power and energy generation facilities
• Fertiliser and agrochemical industries
• Water and wastewater treatment
• Offshore platforms and marine applications
• Pulp and paper mills
• Sulphuric acid and aggressive chemical service
• General industrial utility and high-pressure process lines

In each of these spaces, the combination of strong mechanical integrity, reliable shut-off, and clear position indication makes the bolted bonnet OS&Y design the preferred industrial choice.

Major Valve Body Materials, Compositions & Applications

Choosing the right valve body material is just as important as selecting the right pressure class. The body decides how well the bolted bonnet OS&Y gate valve handles temperature, pressure, mechanical stress, and environmental exposure across different plant conditions.

Common Valve Body Materials

ASTM A351 gr. CF8M – 316 Stainless Steel Molybdenum steel with strong resistance to pitting in chloride solutions, plus excellent strength at elevated temperatures.

ASTM A216 gr. WCB – Carbon Steel Standard service material, usually supplied with CR13SS, stellite, or 316SS trim, with external coating for weather protection.

ASTM A216 gr. LCB Same corrosion properties as WCB, but preferred for low temperature ratings down to -46°C.

ASTM A351 gr. CF3M – 316L Low Carbon Stainless Steel Carbon content of 0.03% or less — ideal where annealing after welding is not practical.

ASTM A351 gr. CF8 – 304 Stainless Steel General-purpose, low-carbon, non-magnetic corrosion-resistant alloy. May be susceptible to chloride stress corrosion cracking.

ASTM A351 gr. CF3 – 304L Low Carbon Stainless Steel Can be used in as-welded condition without inter-granular corrosion concerns. Commonly used where field working is involved.

ASTM A351 gr. CN7M – Alloy 20 Superior resistance in 20–40% sulphuric acid service, with excellent corrosion resistance, mechanical properties, and fabricability.

ASTM A296 gr. CW-12M – Hastelloy C Outstanding performance in oxidising environments with strong resistance to pitting and stress corrosion cracking — even in weld joints.

ASTM A296 gr. M-35 – Monel Excellent resistance to many chemical applications and superior performance in saltwater environments.

Available Valve Body Material Categories

We supply bolted bonnet OS&Y gate valves in a wide range of body materials including Carbon Steel, Low Temperature Carbon Steel, Low Alloys, 13% Cr Stainless Steel, Austenitic Stainless Steel, Precipitation Hardening Stainless Steel, Duplex & Super Duplex Stainless Steel, Bronze, Nickel Alloys (825, 625, 718), and Titanium — allowing us to match every valve to the exact service condition for reliable long-term performance.

Global Reach Across Multiple Industries and Regions

Our bolted bonnet OS&Y gate valves serve a wide global market across multiple continents and heavy industrial sectors.

In North America, our valves are supplied to the United States, Canada, and Mexico. Across Europe, we serve customers in Belgium, Germany, the European Union, the Netherlands, Spain, France, the United Kingdom, Denmark, Sweden, Finland, Poland, Austria, the Czech Republic, Romania, and Italy.

In the Middle East, our valves reach the United Arab Emirates, Qatar, Saudi Arabia, Oman, Bahrain, and Kuwait. Across Africa, we serve Egypt, Nigeria, Kenya, South Africa, Morocco, Tunisia, Ethiopia, Uganda, Tanzania, and many other markets.

In Asia and nearby regions, we supply to Indonesia, Vietnam, Malaysia, Thailand, the Philippines, Singapore, Kazakhstan, Sri Lanka, Japan, South Korea, and others. Our valves also reach Australia, New Zealand, Costa Rica, Colombia, Argentina, Chile, Guyana, Brazil, Panama, Azerbaijan, Turkey, Israel, Ireland, Greece, Jordan, Lebanon, Trinidad and Tobago, the Kyrgyz Republic, and Uzbekistan.

This wide global use clearly shows that our Stainless Steel Gate Valve, super duplex, alloy 20, carbon steel, and ductile iron gate valve designs perform reliably across many international standards, plant conditions, and demanding industrial environments — from oil and gas and refining to chemical processing, power, and offshore applications.

Why Choose Us

Here at Mayur (Valves) System Private Limited, bolted bonnet OS&Y gate valves are treated as serious industrial isolation components, not just standard valves. Our valves are engineered using high-quality body materials, precision-machined trims, robust bolted bonnet construction, and strict quality control protocols aligned with API 600, API 603, and API 598 standards.

We focus heavily on dimensional accuracy, pressure rating compliance, sealing performance, and compatibility with both manual and actuated operation, so every valve installed on your line meets demanding, project-grade requirements. We offer customisation across body materials, trim configurations, pressure classes, and end connections. From the first technical discussion to delivery and after-sales support, our team stays involved at every step — which is exactly why customers across India and global markets continue to choose Mayur (Valves) System Private Limited as their trusted high-performance gate valve manufacturer.

Conclusion

In demanding industrial pipelines, the right gate valve directly decides plant safety, productivity, and long-term operating cost. A well-engineered bolted bonnet OS&Y type gate valve delivers exactly the combination of strong mechanical integrity, reliable full-bore isolation, and clear position indication that modern industries demand. Whether your application calls for a Stainless Steel Gate Valve, super duplex gate valve, alloy 20 gate valve, or carbon steel gate valve, Mayur (Valves) System Private Limited is committed to delivering precision-engineered solutions trusted across global markets — backed by strong engineering, reliable supply, and dedicated technical support.

Looking for high-performance bolted bonnet OS&Y gate valves in Class 150, 300, or 600? Talk to our team at Mayur (Valves) System Private Limited today. Call +91 9998920298 or email mayurvalves@gmail.com for tailored valve solutions.