How to determine the grade of forgings for pressure vessels?_Jiangyin Hengye Forging Co., Ltd-Mechanical hardware-Cartridge

NEWS

Jiangyin Hengye Forging Co., Ltd

company news

Industry News

common problem

How to determine the grade of forgings for pressure vessels?

Release time:

2022-04-08

How to determine the grade of forgings for pressure vessels?

Forgings are frequently encountered in pressure vessel design. How to determine the grade of forgings for pressure vessels? Here, I have sorted out the selection principles to provide you with a reference. Forging refers to a workpiece or billet obtained by forging a metal billet. The mechanical properties of the metal blank can be altered by applying pressure to the metal blank to produce plastic deformation. According to the temperature of the billet during processing, forging can be divided into cold forging, warm forging and hot forging. Cold forging is generally processed at room temperature, warm forging is processed at a temperature higher than room temperature but lower than the recrystallization temperature of the metal blank, and hot forging is processed at a temperature higher than the recrystallization temperature of the metal blank.

Selection principle of forgings for pressure vessels

1. NB/T 47008-2017 "Carbon Steel and Alloy Steel Forgings for Pressure Equipment" Forging Grade 5.4.1 Forgings are divided into four grades: one, two, three and four, and the inspection items and quantities of each grade shall meet the requirements of The requirements for first-class forgings are only applicable to 20, 35, and 16Mn steel forgings with a nominal thickness of less than or equal to 100 mm.

Two: NB/T 47009-2017 "Alloy steel forgings for low temperature pressure equipment" forging grades are divided into two, three and four grades.

3. NB/T 47010-2017 "Stainless steel and heat-resistant steel forgings for pressure equipment" forging grade forgings are divided into four grades: one, two, three, and four. The inspection items and inspection quantities of each grade should meet the requirements of Table 2 . Class I forgings are only suitable for S11306, S11348, S30408 steel forgings with a nominal thickness less than or equal to 150 mm.

4. GB150.2-2011 "Pressure Vessel Part Two: Materials" P58, page 6.1 Carbon steel and low alloy steel forgings, 6.1.3 The grade of steel forgings is specified by the design and indicated on the drawing (grade symbol such as 16Mn and 09MnNiD attached to the steel grade). The following steel forgings shall be grade 3 or 4: a) cylindrical, annular and bowl forgings used for vessel bodies and heads; b) low alloy steel forgings with a nominal thickness greater than 300 mm; c) standard tensile Low-alloy steel forgings with a lower limit of strength equal to or greater than 540 MPa and a nominal thickness greater than 200 mm; d) low-temperature steel forgings with a service temperature lower than -20 and a nominal thickness greater than 200 mm. Page 61, 6.2 High-alloy steel forgings, 6.2.3 The grades of steel forgings are specified by design and indicated on the drawings (a grade symbol is attached after the steel number, such as S30408II). Cylinder-shaped, annular and bowl-shaped forgings used for container barrels and heads should be selected as class or class.

Five: HG/T 20592-2009 "Steel Pipe Flanges" P19 page 4.0.24.0.2 The grade and technical requirements of pipe flange forgings (including forgings) shall meet the following two requirements. 1. If one of the following conditions is met, it should meet the requirements of three or above forgings: 1) The nominal pressure is greater than or equal to PN1002) The chrome molybdenum steel forgings with the nominal pressure greater than PN40; 3) The nominal pressure is greater than PN16, and the working temperature is less than or equal to - 20 ferritic steel forgings. 2 In addition to the above provisions, forgings with a nominal pressure not greater than PN63 should meet the requirements for forgings above grade 2. Intransitive verb HG/T20581-2011 "Steel Chemical Container Material Selection Regulations" page P57, 6.4 6.4.2 Forgings whose size and quality meet one of the following conditions are medium and small forgings, and those exceeding the following conditions are large forgings. 1. The flange size is not larger than the hole flange of PN2.5 and DN600 or other ring forgings of the same size. 2. Pie-shaped, cylindrical and special-shaped forgings (such as tee, valve body, etc.) forging mass should not exceed 800kg. 3. Bar or shaft forgings with diameter not exceeding 200mm and mass not exceeding 1500kg. 6.4.3 Pressure vessel forgings should be selected according to their service conditions, size and quality. 1. Flanges with a design pressure of less than 10.0 MPa and forgings of similar geometric dimensions shall meet the requirements of Class II or above. 2 Forgings with design pressure greater than or equal to 1. 6 MPa should meet the requirements of Class II or above. 3 Small and medium-sized forgings with a design pressure greater than or equal to 10.0MPa should meet the requirements of Class III, and large forgings should meet the requirements of Class III or IV. 4 Forgings with moderate or highly harmful toxicity and forgings with a nominal thickness greater than 300 mm shall meet the requirements of Class III or Class IV.

7. HG/T20585-2011 "Technical Regulations for Steel Low-Temperature Pressure Vessels" P589 Page 6.0.86.0.8 Low-temperature pressure vessel forgings should comply with "Low-alloy Steel Forgings for Low-Temperature Pressure Equipment" NB/T 47009 and "Pressure Equipment" The requirements of NB/T 47010 for stainless steel and heat-resistant steel forgings shall not be lower than the second-level requirements, and when the design pressure is greater than or equal to 1.60Mpa, the third-level requirements shall not be lower.

The above are some references for forgings for pressure vessels. I've extracted all the parts that deal with forging grades here, hopefully it will help you a little bit. For more information, please refer to the page numbers.