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Quality Control of Pressure Bearing Forged Parts (Part Two)

3.3 Quality Control (1) Both JB/T 12000 and NB/T 47008 standards stipulate the quality requirements for pressure-bearing F91 steel forgings used for valve bodies and bonnets. The JB/T12000 standard is divided into four levels, that is, I, II, III, and IV. Level I is generally not applicable. The inspection items of each level are as specified in Table 4. Forgings with pressure above 900lb shall meet the requirements of level III and above. In the design drawings and purchase list,...

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Quality Control of Pressure Bearing Forged Parts (Part One)

Abstract: The process and technical requirements of raw materials, forging, heat treatment, welding and inspection of F91 steel forgings are introduced. The common quality defects are analyzed, and improvement measures are proposed.   1. Overview With the popularization of ultra critical units, ASTM A182 F91 is widely used for high temperatures and high pressures. 91 series steel is a modified steel grade formed by adding strengthening elements V, Nb and N on the basis of 9Cr-1Mo...

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Low-pressure Integrated Flange Forged Lift Check Valves

After conducting independent innovation research on the low-pressure integrated flange forged steel lift check valve and a lot of market research, well communicating with users, collecting users' technical requirements for such products, and understanding the technical performance and quality of imported products, it is found that once failures occur for this series of valves when they are in use, such as leakages, breaking of the valve, resulting...

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Ultra-high Pressure Self Pressure Sealing Forged Gate Valves

In the development of gate valves, the United States has always taken the lead. In the 1960s, the United States began to study the high-pressure gate valve with 105MPa. With the increase in pressure, the structure of the gate valve has also undergone tremendous changes, from a rising stem to a non rising stem. In the 1970s, research on the gate valve focused on materials and processes, and now a series of materials and process forms of gate valve parts have been formed; in the 1980s,...

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Materials and Equipment for Forged Valves

Typical materials for forged valves are as follows: ⑴ Carbon steel series: ASTM A105, ASTM LF2, etc. ⑵ Alloy structural steel series: ASTM A182 F5, ASTM A18 F11, etc. ⑶ Stainless steel series: ASTM A182 F316, F316L, F304, F304L, F321, F347, F310, etc. ⑷ Nickel-based alloys: Hastelloy, Inconel, Monel, etc. ⑸ Copper alloys ⑹ Titanium alloys Changing materials has derived new forging processes and empirical methods, which requires us to continue to explore and...

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Different Forged Valves

Forging supercritical valves Supercritical valves are mainly used in thermal power projects, there is no difference for forging processes for small forgings and conventional forging processes. Large forgings weigh several tons, and forging processes are as follows: ⑴ It is necessary to ensure the correctness of the heating process and a sufficient and suitable forging ratio, because if the forged valve is re-heated, the grains will recrystallize and grow through the external...

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Domestic Development Status of Forged Steel Valves

In recent years, detailed and thorough research and test verification on valves are conducted in scientific research institutes, universities, professional institutions, and manufacturing plants. China's low and medium end valves have absolute speaking right in the world. Under the guidance of China's technological research policies, we have actively engaged in the development and research of high-end valves and made great progress. Most products are comparable...

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The Classification and Market Demand of Forged Steel Valves

The forging process of valve forgings may seem simple, but it is complex and changeable. Valves are used in all walks of life. There are many new materials and new processes which require time to repeatedly practice and study, and there is also some new knowledge that needs to be studied and discussed. Valve forgings in the fields of nuclear power, military industry, LNG, hydrogenation, and petrochemicals are only introduced in this article, including the introduction...

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The Structural Design of Forged Slab Gate Valves without Welding Seams

A kind of forged slab gate valve without a welding seam is introduced, and its overall structure, bonnet structure, installation methods of valve seats and connections between valve stems and valve plates are introduced in this article, which reflects the practicability and maneuverability of the product in terms of structure, technology, performance and so on. The product has been patented.   1. Overview With the continuous progress of modern technology and industry,...

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Temperature Field Calculation & Thermo-solid Coupling Analysis of High-temperature Forged Gate Valves (Part Three)

5. The calculation of the thermo-solid coupling stress field of forged gate valves under high-temperature conditions The temperature field obtained by the steady state thermal analysis has a significant influence on strain and stress in the structural analysis, but the structural response will not have a great influence on the thermal analysis results. Therefore, the thermal stress analysis involved in the thermo-solid coupling calculation of the forged...

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Temperature Field Calculation & Thermo-solid Coupling Analysis of High-temperature Forged Gate Valves (Part Two)

3. The calculation of the temperature field of the gate valve under high-temperature conditions 3.1 Boundary conditions and loads The calculation of the temperature field of the gate valve is conducted by the function of the thermal analysis in Ansys. Ansys thermal analysis is divided into steady-state thermal analysis and transient thermal analysis. Steady-state heat transfer means that the temperature of the system does not change with time, while transient heat transfer...

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Temperature Field Calculation & Thermo-solid Coupling Analysis of High-temperature Forged Gate Valves (Part One)

Abstract Given the design requirements for high-temperature forged steel gate valves, the virtual performance evaluation technology of gate valves is studied based on standard specifications and finite element analysis methods of the American Society of Mechanical Engineers (ASME). To ensure the safe and reliable operation of gate valves under high-temperature conditions, a method for calculating the temperature and stress field of high-temperature forged steel gate valves...

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Research on Generalization of Forged Steel Hydrogenation Valve Bodies Based on the Finite Element

Abstract: Aiming at the problems of high manufacturing costs and long production cycles of forged steel hydrogenation valve bodies, take two Y-shaped forged steel globe valves with a diameter of 10IN and pressure of 1500LB and 2500LB as an example. Universal and innovative design is carried out for the forged steel valve bodies with the same diameter and different pressure. The finite element analysis software Patran is used for the static analysis, and the...

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Design and Research of Forged Slab Gate Valves without Welding Seams

Forged slab gate valves without welding seams made from nickel alloy 625 with pressure of Class 900 and 15% of H2S content in the medium have advantages under conditions of high requirements and strong corrosion. They have good practicability and operability in practical applications, and bright prospects of the market promotion.   1. Overall structure The main parts of the forged slab gate valve without welding seams, such as the valve...

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An Introduction to a Forged Steel Ball Valve

The features and applications of a forged steel ball valve A forged steel ball valve has features of good performance, good reliability, wide ranges of applications and reasonable prices. It can be classified into low-pressure forged steel ball valves and high-pressure forged steel ball valves. A forged steel ball valve is applied to chemical, petroleum, natural gas, metallurgy and long-distance natural gas pipelines containing hydrogen sulfide, many...

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The Connection Ends and Maintenance of the Forged Steel Valve

Most of the forged steel valves have flange ends, and there are the following types according to the shape of the connecting surface: 1. Lubrication types: they are used for forged steel valves with low pressure, and the processing is convenient. 2. Concave-convex types: the operating pressure is high, and gaskets with medium hardness or good hardness can be used. 3. Tongue and groove types: gaskets with great plastic deformation can be used, which are...

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Processing Oblique Channels of Forged Steel Globe Valve Bodies (Part Two)

3. The structure of positioning fixture (1) The structure of the fixture The optimized positioning fixture is composed of a mold, a positioning screw, a nut, a pressure plate, a spacer block, a T-slot screw, etc. (Figure 3) (2) The principle of clamping  The centerline of the two channels of the valve body is parallel to that of the spindle of the machine tool through the inclined surface of the mold, and the channel at one end of the valve body is matched with the eccentric port by the eccentric...

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Processing Oblique Channels of Forged Steel Globe Valve Bodies (Part One)

Abstract: The structural characteristics of the oblique channel of the high-pressure forged steel globe valve body and its processing method are discussed in this article, and the contrast analysis is carried out in aspects such as the processing accuracy, processing range, and processing efficiency. Through the conclusions drawn, the positioning fixture of the lathe is optimized and improved. According to the type and characteristics of the machine tool equipment, economical and applicable processing...

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The Machining of Oblique Holes of Forged Steel Globe Valve Bodies

The compact forged steel globe valve has small sizes, light weights, good strength and reasonable structure, which is welcomed by users. The machining processes of the globe valve body (Figure 1) are as follows: die forging valves → heat treatment → shot blasting → inspection → machining middle flange planes, seam allowance and middle holes → machining both end faces, socket and flow holes → drilling the flange bolt holes of middle flanges → drilling the oblique...

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Stellite Alloy Surfacing Repair Processes of 15CrMo Forged Gate Valves (Part Three)

3.1.3 Intelligent temperature control The temperature rise rate should not exceed 70℃/h to avoid the partial excessive temperature of the valve body and valve seat, which will affect the deformation of the valve body. After it exceeds 300°C, the heating rate is allowed to be appropriately reduced. When the temperature rises to about 370°C, you can weld the parts that need surfacing after heat preserving for about 2 hours. The schematic diagram of the...

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