GB/T 30583-2014Specification for post weld heat treatment of pressure equipment (English PDF)

4.1 General provisions

4.1.1 In addition to complying with this Standard, the post weld heat treatment of pressure equipment shall also comply with the requirements of product standards, design documents and contracts.

4.1.4 The constructer of pressure equipment shall have technical personnel, who have certain professional knowledge and sufficient practical experience, after they master the following basic conditions, prepare "Process specifications for post weld heat treatment" for each (piece) weldment.

4.1.5 The welding process evaluation items used for weldments shall include all important factors and supplementary factors that may occur during the implementation of the "Process specifications for post weld heat treatment".

4.2 Post weld heat treatment thickness deltaPWHT

4.2.1 The deltaPWHT of equal thickness full penetration butt joint is the weld thickness (excess height is not counted). At this time, deltaPWHT is the same as the base metal thickness.

4.2.4 The values of deltaPWHT when welding pressure components with different

thicknesses are as follows (see Annex A).

4.2.5 Thickness of post weld heat treatment calculation holding time.

4.3 Post weld heat treatment methods

4.3.3 Partial post weld heat treatment

4.4 Specification parameters of post weld heat treatment

4.4.1 The specification parameters of post weld heat treatment are shown in Table 1.

4.4.1.1 For Fe-1 and Fe-3 steel weldments, when the post weld heat treatment is performed below the minimum holding temperature in Table 1, the holding time can be extended as specified in Table 2.The holding temperature of Fe-9B steel weldments shall not exceed 635°C. When the post weld heat treatment is performed below the minimum holding temperature in Table 1 (up to 55°C reduction is allowed), the holding time can be extended according to the provisions of Table 2.

4.4.1.5 Limits of post weld heat treatment temperature for Fe-5B-2 steel weldments

under the following conditions.

4.4.2 The holding time of post weld heat treatment can be completed in one heat treatment process. It can also be the accumulation of multiple heat treatment processes at the same holding temperature.

4.4.3 Unless otherwise specified, the temperature of each temperature measurement

point is allowed to be within ±20°C of the specified temperature of the heat treatment process but cannot exceed the specified limit.

5.3 Insulation materials, temperature control instruments and temperature measuring

instruments shall meet corresponding standards. The product shall have quality certificate and instruction manual.

5.4 Manufacturers of thermocouples and compensation wires shall have corresponding qualifications. The used thermocouple and compensation wire shall have quality certificate.

5.5 All kinds of measuring instruments shall pass the measurement inspection according to the standard. Before use, calibrate as specified.

5.6 The post weld heat treatment heating, temperature control, temperature

measurement device and the whole system outside the furnace shall be inspected and debugged each time before being put into use. Make them in a normal state and meet the heat treatment requirements.

5.7 The thermal insulation material shall not contain elements and impurities that are harmful to the weldment. It is advisable to use aluminum silicate fiber and its products, high silica cloth, alkali-free glass fiber cloth.

6.3 Remove the non-permanent connections on weldments not related to post weld heat

treatment.

6.4 Effective measures shall be taken for finishing surfaces such as sealing surfaces and screw holes of weldments, so as to prevent high temperature oxidation.

6.5 When performing post weld heat treatment outside the furnace, the heating

equipment shall have sufficient power reserve.

7.1 Technical requirements

7.1.1 When performing post weld heat treatment in the furnace, according to the

technical requirements of the weldment, the corresponding type of heat treatment furnace shall be selected in accordance with the provisions of GB/T 9452.Weldments shall be placed within the effective heating area.

7.1.3 The heating medium shall avoid spraying the weldment directly.

7.1.4 The heating medium shall not cause oxidation, decarburization, carburization and corrosion on the surface of the weldment that exceeds the depth specified in the technical documents.

7.2 Regulations for post weld heat treatment furnaces and instruments

7.2.1 The detection period of the effective heating area of the post weld heat treatment furnace is 6 months. For the heat treatment furnace of normal use that has passed the inspection for 3 consecutive cycles, the detection period can be extended to 1 year.

7.2.4 The temperature measurement system of the post weld heat treatment device shall be regularly calibrated under normal use. During calibration, the distance between the hot ends of the detection thermocouple, temperature measurement thermocouple and temperature control thermocouple shall be close.

8.1 Temperature measuring points and their arrangement

Figure 2 -- Thermocouple arrangement spacing diagram

8.1.4 Additional thermocouples can be added for temperature measurement points in important parts.

8.1.5 The number of temperature measurement points and their arrangement shall be indicated in the design drawing or schematic diagram of the weldment.

8.2 Welding requirements for capacitor energy storage points

Use welding methods (such as capacitor energy storage spot welding) to connect thermocouples to weldments. The welding requirements for capacitor energy storage points are as follows.

8.3 Temperature measurement

8.3.1 During the post weld heat treatment and heat holding period, the temperature of any point on the weldment of the overall post weld heat treatment and the temperature of any point within the volume range shown in the soak band of the weldment of the partial post weld heat treatment shall be within the specified range.

8.3.2 The post weld heat treatment temperature is subject to direct measurement on the weldment.