局部焊后热处理程序LOCAL PWHT PROCEDURE.doc

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1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流局部焊后热处理程序LOCAL PWHT PROCEDURE.精品文档.局部焊后热处理程序LOCAL PWHT PROCEDURETable of Content1. PURPOSE . 22. SCOPE . 23. REFERENCES. 24. METHOD OF PWHT. 25.REQUIREMENTS. 35.1 PREPARATION PRIOR TO PWHT . 35.2 EXECUTION OF PWHT. 55.3 PWHT RECORD SYSTEM. 51. PURPOSEDuring installations of

2、 the 5 feedstock tanks, some parts will be carried out PWHT on site. This procedure is issued to ensure that PWHT can carry out smoothly, and that parameters and quality of PWHT can meet requirements of contract, and applied pecification/standard to satisfy the owner.目的：原料油储罐安装过程中，一些部件需进行现场热处理，本程序的发

3、布，是为了保证现场热处理工作的顺利进行，使热处理参数、质量符合合同、适用规范和标准的要求，使业主满意。2. SCOPEThis procedure is applicable to local PWHT of manholes, nozzles, and reinforcement plates of 5 feedstock tanks of XX Xx Petrochemical Project. If manholes and nozzles are with reinforcement plates, and thickness of plate which man-hole and n

4、ozzle are in is more than 12mm, PWHT shall be carried out after man-holes, nozzles, and reinforcement plates have been assembled and welded with the plate which they should be in, and they are accepted.范围：本施工程序适用于xx石油化工有限公司原料油罐安装中，对人孔、接管及补强板的热处理施工。如果人孔、接管带有补强板，并且所在壁板的厚度大于12mm，那么，在补强板及开口接管与相应罐壁板组装焊接并

5、检验合格后，应进行消除应力热处理。3. REFERENCES3.1 “Vertical cylindrical steel welded oil tank” GBJ128-903.2 “Welded Steel Tanks for Oil Storage” API- 6503.3 PMC Relevant Welding Procedures XX-00383.4 WELDING OF METALS XX.18-XX3.1立式圆筒形钢制焊接油罐施工及验收规范 GBJ128-903.2钢制焊接油罐 API- 6503.3 PMC 相关焊接文件 XX-00383.4 金属的焊接XX.18-XX4.

6、 Method of PWHTPost Weld Heat Treatment (PWHT) is heat treatment carried out after welding with the aim to reduce residual stresses and to restore toughness properties after degradation by welding.The method of PWHT is electric heating. The caterpillar electric heater and linear electric heater shou

7、ld be fixed on the parts needed to PWHT, they connect with the automatic controller through cable. And thethermocouple should be fixed on the parts needed to PWHT through the compensating conductor, it connects with the computer automatic controller. Then the controller will work automatically accor

8、ding to the process parameter that is being inputted into the controller.热处理方法PWHT 是焊后进行的热处理，目的是减少残余应力，恢复由于焊接而降低的韧性。热处理方法采用电加热。把履带式电加热片、绳状电加热器固定到需热处理部位，通过电缆与自动温控记录设备连接，把热电偶固定到需热处理部位，通过补偿导线与电脑自动温控记录设备连接。向该设备输入热处理工艺参数，设备自动按所定热处理工艺参数进行热处理。5.REQUIREMENTS5.1 Preparation prior to PWHT热处理前准备5.1.1 Inspectio

9、n of welding seam Welding seam in PWHT area should be accepted through NDE, reinforcement plate should be accepted after the inspection of air tightness, and inspection report should also be prepared.焊缝检查热处理部位的焊缝应是探伤合格的，补强板是经过气密检查合格的，并有检查报告。5.1.2 Reinforcing of workpieceIf DN500mm, the manhole and n

10、ozzle should be reinforced through L100 angle iron to prevent the distortion of workpiece. As the drawing listed below, angle iron should be welded on the workpiece. AfterPWHT, angle iron should be removed, and PT should be done to the palace where the angle iron is removed.工件加固对 DN500mm 的人孔、接管，L100

11、 用的角钢进行加固，防止工件产生变形。如下图所示，角钢焊接在工件上。热处理后，把角钢磨除，磨除处进行PT。5.1.3 Fixing of electric heater Linear electric heater may wrap around the fillet weld between manhole and nozzle, the caterpillar electric heater should be fixed on the shell and the reinforcement plate through bar for line and steel wire.The hea

12、ters should be lay out in the inside and outside of the tank shell.电加热片固定绳状电加热器可缠绕在人孔、接管与罐壁的角焊缝位置，履带式电加热片用保温钉和钢丝绑扎固定在罐壁和补强板上，在罐壁内外双面布置。5.1.4Thermocouple attachments should be:- capacity discharge connection, or- nut and bolt construction (as shown below)Two tack welds (opposite each other)Thermocoup

13、le insertionIf the latter method is used, the materials should be of a compatible composition. The weld metal shall be removed by careful dressing followed by MT or PT examination after PWHT to confirm absence oflinear indications.All thermocouple attachments shall be adequately insulated to avoid t

14、emperature misreading caused bythe effect of radiation.The number and positions of the thermocouples shall be in accordance with the following:-For the nozzle fillet weld, one thermocouple should be lay out outside and inside respectively, and the two positions should be symmetrical.-For the seam of

15、 reinforcement plate, two thermocouples should be lay out outside of shell opposite each other.-The thermocouple should be placed in the distance of 520mm from the fringe of the welding seam.热电偶固定热电偶应该采用：-电容放电连接，或-螺母螺栓连接（螺母对称点焊两点，插入热电偶）。如果采用后一种方法，材料应是相配的。热处理后，焊接金属仔细修磨去掉，进行 MT 或PT，确保没有线性指示。所有热电偶应该足够隔

16、热，避免散热引起的温度读数偏差。热电偶的数量和位置按以下要求：-对于接管角焊缝位置，在罐壁内外各一点，交错对称布置；-对于补强板焊缝位置，在罐外侧对称布置两点；-热电偶在距焊缝边缘外520mm 处。5.1.5 保温Heat preservationHeat preservation material should be alumina silicate fibrofelt, and the thickness of heat preservation should be about 100mm, the fibrofelts should be fixed by iron wire and b

17、ar for line welded in the tankshell temporarily. The distance of 800mm from the electric heating welding seam should be heat preserved, the bodies of manhole and nozzle also should be heat preserved.保温材料选用硅酸铝纤维毡，保温厚度100mm，纤维毡利用焊在罐壁上的保温钉绑扎铁丝固定。热处理焊缝以外800mm 内均应保温，人孔、接管本身也应保温。5.1.6 PWHT equipmentPWHT c

18、ontrollers and time-temperature recorders shall be properly calibrated and maintained in good working order at all times. The recorders shall be procured with a calibration certificate, and shall bere-calibrated at the stated intervals in accordance with the Contractors approved calibration procedur

19、es.Each equipment should be connected through conductors.热处理设备热处理设备包括热电偶、时间 温度记录仪、和控制器。它们应加以正确校准并保持良好的工作状态。热电偶、记录仪应具有校准证明书，并且应依据承包商批准的校准程序在规定的时间间隔内重新校准。各个设备用导线连接好。5.2 Execution of PWHTAfter the preparation has completed, PWHT should be carried out. Input the process parameter into the controller and

20、 put on the switch, and then PWHT begins to carry out.PWHT process parameter sees the following:Heat treatment temperature： 600650Holding time: 160 minutesHeating speed: 150/hCooling speed: 160 minutes升温速度：150/h降温速度：210/h说明：300以下时，升温速度和冷却速度不需控制，但不应太高。热处理曲线见下图：5.3 PWHT Record System焊后热处理记录系统Time-Temp

21、erature Charts (Post Weld Heat Treatment Charts) and PWHT reports of each post weldheat-treating operation shall be provided. Heat treat records shall indicate:应提供每个焊后热处理操作的时间 温度图（焊后热处理图）和热处理报告。热处理记录应包括：Applicable code 采用的规范Identification of joints or pieces 接头或工件的识别号Project identification 项目识别号Date

22、 of post weld treatment 焊接后热处理日期Signature of PWHT supervisor and QC Welding Inspector焊接后热处理主管及质量控制焊接检验员的签名Wall thickness 壁厚Heating rate 加温速率Chart speed 记录纸速Hold time 保温时间Hold time begin 保温开始时间Hold time end 保温结束时间Power off time 电源断开时间Cooling rates 冷却速率5.4 NDE after PWHTAfter the completion of PWHT, MT or PT should be done to welding seam in the area of PWHT,and no crack is accepted.No welding or heating shall be carried out after final PWHT.热处理后 NDE热处理完成后，对热处理区域内的焊缝进行MT 或PT，无裂纹为合格。热处理完成后,不能再进行焊接和加热。