Alloy steel flanged pipe fittings are special pressure-bearing components in high-temperature and high-pressure piping systems. They use chromium-molybdenum alloy steels such as 15CrMo, 12Cr1MoV, Cr5Mo, P11, P22, and P91 as base materials, are formed by integral forging, and are suitable for high-temperature, high-pressure, hydrogen-containing, and thermal cycling conditions that ordinary carbon steel and stainless steel cannot handle. The products cover structural forms such as flanges, elbows, tees, and reducing plugs, with pressure ratings covering PN25–PN160 and Class150–Class2500, and nominal diameters covering DN15–DN1200. We can produce according to standards such as ASTM A182, ASTM A234, GB/T12459, HG/T20592, and ASME B16.5, and support customization requirements such as non-standard dimensions, special sealing surfaces, quenched and tempered heat treatment, and non-destructive testing. Before purchasing, it is recommended to provide the medium temperature, pressure rating, material grade, and connection standard, and we will assist in confirming the selection and delivery plan.
Product Overview
Alloy steel flanged pipe fittings are used in piping systems for high-temperature and high-pressure, hydrogen service, and thermal cycling conditions, using chromium-molybdenum and chromium-vanadium alloy steel as the base material, formed through integral forging. Compared with ordinary carbon steel and stainless steel pipe fittings, their creep resistance, hydrogen embrittlement resistance, and thermal fatigue resistance at high temperatures are better suited to scenarios such as power stations, refining and chemical processing, and coal chemical industries. Products cover structures such as flanges, elbows, tees, and reducing plugs, and can perform functions of pipeline connection, direction change, flow splitting and merging, reducing and plugging, and equipment connection. We can produce according to standards such as ASTM A182, ASTM A234, GB/T12459, HG/T20592, ASME B16.5, and support customization according to project drawings.
Key Features
In terms of material, we provide chromium-molybdenum alloy steels such as 15CrMo, 12Cr1MoV, Cr5Mo, P11, P22, and P91, which can be matched to different temperature gradients including within 450°C, above 500°C, and supercritical conditions. In terms of structure, integral forging results in a dense metallographic structure that is not prone to softening and deformation at high temperatures. In terms of sealing, precision sealing surfaces can be machined to meet the fitting requirements under high pressure and high temperature. In terms of specifications, pressure ratings cover PN25–PN160 and Class150–Class2500, and nominal diameters cover DN15–DN1200. In terms of inspection, before leaving the factory, spectral material verification, dimensional calibration, precision inspection of sealing surfaces, non-destructive testing, and hydrostatic testing are carried out. In terms of customization, we support non-standard thickened wall thickness, special reducers, irregular flange hole spacing, non-standard high-pressure sealing surfaces, and quenched and tempered heat treatment.
Applications
In the electric power and thermal power field, it is used for main steam pipelines of thermal power plants, high-temperature auxiliary equipment pipe networks of boilers, high-pressure systems of supercritical units, and high-temperature circulation pipelines of combined heat and power generation. In the petrochemical and refining field, it is used for high-pressure oilfield gathering and transportation, high-temperature refining process pipelines, high-pressure natural gas pipelines, and hydrogen refining systems. In the coal chemical field, it is used for high-temperature reactor connections, high-pressure synthesis pipelines, and acid-base high-temperature alternating process pipe networks. In the special equipment field, it is used for high-temperature ports of pressure vessels, high-pressure valve group systems, high-pressure instrument pipelines, and boiler-matched pressure-bearing systems. In the new energy field, it is used for high-temperature energy storage pipelines and high-pressure process equipment pipe networks for hydrogen energy.
Specifications
Commonly used materials include 15CrMo, 12Cr1MoV, Cr5Mo, P11, P22, and P91. Pressure ratings cover PN25–PN160 and Class150–Class2500, and nominal diameters cover DN15–DN1200. Executive standards include ASTM A182, ASTM A234, GB/T12459, HG/T20592, ASME B16.5, etc. Product classification is flanges and stub ends, and the brand is Guojie. For specific models, wall thickness, sealing surface forms, and special technical requirements, please contact us for confirmation.
Purchase & Delivery
For conventional DN15–DN200 15CrMo, 12Cr1MoV, P11, and P22 stock styles, re-inspection is completed within 24 hours after order confirmation. We set flexible tiered minimum order quantities, which can accommodate needs such as sporadic replacement parts, technical modifications, samples, and bulk centralized procurement. For specific minimum order quantities, please contact us for confirmation. Packaging adopts an anti-collision, anti-scratch, anti-rust, moisture-proof, and non-destructive testing protection system; sealing surfaces and precision-machined end faces are covered with protective film; threaded ports and bolt holes are fitted with protective plugs; small and medium diameters are individually wrapped and then boxed; medium and large diameters are wrapped with anti-rust oil paper and waterproof film; full-container shipments are stacked on fumigation-free solid wood pallets and secured with steel straps. English shipping marks, material grades, non-destructive testing numbers, and customer LOGOs can be customized. Delivery time is confirmed according to order specifications and quantities.
Service & Support
In the pre-sales stage, we can assist in matching materials, pressure ratings, and sealing structures according to medium temperature, pressure rating, hydrogen service conditions, and equipment parameters. In the after-sales stage, we provide technical guidance for installation, hot tightening specifications, pressure testing and commissioning, and special equipment inspection declaration, and assist overseas customers with rapid customs clearance. Products have an 18-month warranty and 7×24-hour response. For quality issues caused by factory forging, heat treatment, precision machining, or non-destructive testing processes, we support free returns and exchanges, free re-inspection, and free replacement shipment.
FAQ
What is the difference between alloy steel pipe fittings and carbon steel and stainless steel pipe fittings?
Alloy steel flanged pipe fittings, by adding alloying elements such as chromium, molybdenum, and vanadium, are designed for high-temperature and high-pressure working conditions in terms of high-temperature resistance, creep resistance, hydrogen embrittlement resistance, and thermal fatigue resistance. Carbon steel is usually used for medium- and low-pressure normal-temperature pipelines, and stainless steel has limited creep resistance and thermal deformation resistance under high temperature and high pressure. If your working conditions involve high-temperature steam above 500°C, high-pressure hydrogen service, or thermal cycling, it is recommended to prioritize alloy steel materials.
How to select commonly used alloy materials?
For conventional conditions within 450°C, 15CrMo, 12Cr1MoV, or P11 can be selected; for high-temperature working conditions above 500°C, P22 can be selected; for supercritical high-temperature and high-pressure working conditions, P91 can be selected. The specific selection needs to be combined with the medium temperature, pressure rating, and hydrogen service conditions. You are welcome to provide the working condition parameters, and we will assist in confirming.
What advantages does the RJ sealing surface have?
The RJ metal ring connection is a hard-seal structure. Under high-temperature and high-pressure and thermal cycling conditions, it fits tightly, and its resistance to thermal deformation and pressure impact is relatively good, making it suitable for high-pressure pipelines with high requirements for sealing durability. Whether to choose the RJ sealing surface needs to be confirmed in combination with the flange standard, pressure rating, and medium characteristics.
How are the minimum order quantity and delivery time confirmed?
We set flexible tiered minimum order quantities, which can accommodate needs such as sporadic replacement parts, technical modifications, samples, and bulk centralized procurement. For conventional DN15–DN200 15CrMo, 12Cr1MoV, P11, and P22 stock models, re-inspection is completed within 24 hours after order confirmation. For the specific minimum order quantity and delivery time, please contact us and provide the specifications, material, and quantity.
Is non-standard customization supported?
Yes. Dimensional customization covers DN15–DN1200, and non-standard thickened wall thickness, special reducing size ratios, special-shaped flange hole spacing, and non-standard high-pressure sealing surfaces can be customized. Materials can cover the entire series of chromium-molybdenum heat-resistant alloys, including 15CrMo, 12Cr1MoV, Cr5Mo, P11, P22, and P91. Production can be carried out according to overseas drawings, engineering technical agreements, and special equipment specifications, and English shipping marks, exclusive LOGO, and flaw detection numbering customization are supported.
