Sampling / Specimen Removal Procedure-取样/试样移除程序

以下是针对管件及法兰的原材料取样/样品移除程序。这份文件适用于需要进行理化检验（如拉伸试验、冲击试验、硬度试验、金相分析等）时的破坏性取样场景。

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管件及法兰原材料取样/样品移除程序

1. 目的

规范管件及法兰在入场检验或复验过程中，用于理化试验的样坯（样品）的取样、标记、移除及后续处理流程，确保样品的代表性和试验结果的准确性，同时保证剩余本体的可追溯性和可用性。

2. 适用范围

适用于需进行破坏性检测的各类钢制管件（弯头、三通、异径管、管帽）和钢制法兰的原材料取样。

3. 取样依据

· 产品执行标准（如ASTM A960、ASME、GB/T 13401）

· 采购技术规格书或检验计划

· 试验方法标准（如GB/T 228.1、 ASTM E8/E8M）

4. 取样原则

1. 代表性：所取样品必须能代表该批次材料的真实性能。

2. 最小破坏：在满足试验需求的前提下，尽量减小对原产品的破坏。

3. 可追溯性：样品与母材的标识必须唯 一且对应。

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5. 取样程序

5.1 取样时机

通常在原材料接收检验（外观、尺寸合格后）进行，或在监理/客户要求进行第三方复验时执行。

5.2 取样位置与方法

A. 法兰取样

· 拉伸/冲击样坯：

  · 首 选位置：法兰本体轮缘（外缘） 处或颈部加厚部位。这些区域有足够的余量加工标准试样。

  · 取样方向：一般取切向（垂直于半径方向）或纵向。

  · 移除方法：使用带锯或火焰切割（碳钢）从法兰边缘切取楔形块。严禁从法兰密封面或螺栓孔附近取样。

· 硬度检测：

  · 通常在法兰本体外圆柱面或轮毂端面进行打磨后直接测试，一般不涉及样品移除。

B. 管件取样

· 弯头：

  · 拉伸样坯：通常取自身背部（外弧侧） 或腹部（中性面） 的延长段。避开热加工变形最剧烈的区域。

  · 冲击样坯：如需做低温冲击，应在背部取样。

· 三通：

  · 拉伸样坯：取自主管本体或支管本体上应力较小的区域。

· 异径管/管帽：

  · 拉伸样坯：取自大端本体。

· 移除方法：

  · 推荐方法：使用机械切割（如带锯床），可避免热影响区改变材料性能。

  · 火焰/等离子切割：仅允许用于碳钢且有余量（粗切），必须预留足够的加工余量（通常单边≥5mm），以便在后续机加工时完全去除热影响区。

  · 严禁：严禁在管件的焊接坡口边缘直接取样，以免破坏后续的焊接接口。

5.3 取样尺寸

所切取样坯的尺寸应大于最终试样的尺寸。通常毛坯尺寸为：

· 拉伸试样：长度 ≥ 200mm，宽度 ≥ 40mm，厚度取原壁厚。

· 冲击试样：通常需切取 80mm × 80mm 的块体，或按 15mm × 15mm × 60mm 的毛坯预留。

5.4 样品标识

样品切下后，必须在3秒内完成标识转移：

1. 原始标识：在母材切割位置旁，用记号笔或钢印重新标记炉批号或追踪号。

2. 样品标识：在样品本体上焊接标签牌、打钢印（注意避让最终机加工面）或系挂防水金属标签。

   · 标识内容：炉批号 + 样坯编号 + 材料牌号。

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6. 样品移除后的处理

6.1 母材（剩余本体）处理

1. 标记封存：在切割缺口处，喷涂黄色“取样试验件”标识，注明取样日期和检验状态。

2. 隔离：该件产品应暂时隔离在“待处理区”，不可直接流入成品库。

3. 最终处置：

   · 报废：如果取样导致产品尺寸不完整或强度受损，该产品应转入废品库，随试验报告一起报废处理。

   · 保留：如果取样缺口较小且不影响使用（如从法兰外缘切取的小块），经设计或质检负责人评估后，可进行补焊（需按焊接工艺评定执行）或作为保留件用于非关键部位。

6.2 样品流转

1. 委托：填写《理化检验委托单》，注明取样位置（如“弯头背部”）和检测项目。

2. 加工：将样坯送至机加工车间，按标准尺寸加工成标准试样。

3. 试验：加工好的试样送至实验室进行测试。

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7. 常见取样缺陷及规避

1. 过热/过烧

   · 现象：火焰切割时，切割面熔化严重，晶界氧化。

   · 规避：留足机加工余量（碳钢至少3-5mm）；不锈钢尽量采用机械切割或等离子切割+大余量。

2. 变形

   · 现象：薄壁管件切割时发生翘曲。

   · 规避：采用低速带锯或手工锯，减少热输入和机械应力。

3. 混样

   · 现象：切割后样品标签脱落或混淆。

   · 规避：执行双标识（样品上+容器袋上），并严格执行“先标识，后切割”原则。

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8. 安全注意事项

1. 动火作业：火焰切割必须办理动火证，配备灭火器。

2. 固定：切割前必须将管件/法兰牢固夹持在台钳或切割机上，防止掉落伤人。

3. 锐边处理：切割后的样坯边缘锋利，必须及时倒角或打磨，防止划伤。

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附：取样记录表示例

The following is the raw material sampling/sample removal procedure for pipe fittings and flanges. This document is applicable to destructive sampling scenarios that require physical and chemical testing (such as tensile testing, impact testing, hardness testing, metallographic analysis, etc.).

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Sampling/sample removal procedures for raw materials of pipe fittings and flanges

1. Purpose

Standardize the sampling, marking, removal, and subsequent processing procedures of the sample blank (sample) used for physical and chemical testing during the entry inspection or re inspection of pipe fittings and flanges, ensuring the representativeness of the sample and the accuracy of the test results, while ensuring the traceability and usability of the remaining body.

2. Scope of Application

Suitable for sampling raw materials of various steel fittings (elbows, tees, reducers, caps) and steel flanges that require destructive testing.

3. Sampling basis

·Product execution standards (such as ASTM A960, ASME, GB/T 13401)

·Procurement Technical Specification or Inspection Plan

·Test method standards (such as GB/T 228.1, ASTM E8/E8M)

4. Sampling principle

1. Representativeness: The sample taken must be able to represent the true performance of the batch of materials.

2. Minimum damage: Minimize damage to the original product while meeting the testing requirements.

3. Traceability: The identification of samples and base materials must be unique and corresponding.

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5. Sampling Procedure

5.1 Sampling timing

Usually conducted during the raw material acceptance inspection (after the appearance and dimensions are qualified), or when the supervisor/customer requests a third-party re inspection.

5.2 Sampling location and method

A. Flange sampling

·Stretch/Impact Prototype:

·Preferred location: at the rim (outer edge) of the flange body or at the thickened part of the neck. These areas have sufficient margin to process standard samples.

·Sampling direction: generally taken in the tangential direction (perpendicular to the radius direction) or longitudinal direction.

·Removal method: Use a band saw or flame cutting (carbon steel) to cut wedge-shaped blocks from the edge of the flange. It is strictly prohibited to take samples near the flange sealing surface or bolt holes.

·Hardness testing:

·Usually, direct testing is carried out after polishing the outer cylindrical surface of the flange body or the end face of the wheel hub, without involving sample removal.

B. Sampling of pipe fittings

·Bend:

·Stretch sample blank: usually taken as an extension of the back (outer arc side) or abdomen (neutral surface) of the body. Avoid the areas with the most severe deformation during hot processing.

·Impact sample blank: If low-temperature impact is required, samples should be taken from the back.

·Three links:

·Stretch sample blank: taken from the area with lower stress on the main or branch pipe body.

·Reducing pipe/cap:

·Stretch sample blank: taken from the large end body.

·Removal method:

·Recommended method: Use mechanical cutting (such as a band saw) to avoid changing material properties in the heat affected zone.

·Flame/plasma cutting: only allowed for carbon steel with allowance (rough cutting), sufficient machining allowance must be reserved (usually ≥ 5mm on one side) to completely remove the heat affected zone during subsequent machining.

·Strictly prohibited: It is strictly prohibited to directly sample at the edge of the welding groove of the pipe fittings to avoid damaging the subsequent welding interface.

5.3 Sampling size

The size of the cut sample should be larger than the size of the final sample. The usual blank size is:

·Tensile test specimen: length ≥ 200mm, width ≥ 40mm, thickness taken from the original wall thickness.

·Impact test specimen: Typically, 80mm x 80mm blocks need to be cut, or 15mm x 15mm x 60mm blanks need to be reserved.

5.4 Sample Identification

After cutting the sample, the identification transfer must be completed within 3 seconds:

1. Original identification: Next to the cutting position of the base material, use a marker pen or steel stamp to re mark the furnace batch number or tracking number.

2. Sample identification: Weld label plates, stamp steel seals (avoiding the final machined surface) or hang waterproof metal tags on the sample body.

·Identification content: furnace batch number+sample billet number+material grade.

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6. Processing after sample removal

6.1 Processing of Base Metal (Remaining Body)

1. Marking and sealing: Spray a yellow "sampling test piece" label at the cutting gap, indicating the sampling date and inspection status.

2. Isolation: The product should be temporarily isolated in the "processing area" and cannot be directly sent to the finished product warehouse.

3. Final disposal:

·Scrap: If the sampling results in incomplete product size or damaged strength, the product should be transferred to the scrap warehouse and scrapped together with the test report.

·Retention: If the sampling gap is small and does not affect use (such as small pieces cut from the outer edge of the flange), after evaluation by the design or quality inspection responsible person, it can be repaired by welding (according to the welding process qualification) or used as a retention part for non critical parts.

6.2 Sample circulation

1. Commission: Fill out the "Physical and Chemical Inspection Commission Form", indicating the sampling location (such as "bend back") and testing items.

2. Processing: Send the sample blank to the machining workshop and process it into standard samples according to standard dimensions.

3. Experiment: The processed sample is sent to the laboratory for testing.

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7. Common sampling defects and their avoidance

1. Overheating/Overheating

·Phenomenon: During flame cutting, the cutting surface melts severely and the grain boundaries oxidize.

·Avoidance: Leave sufficient machining allowance (at least 3-5mm for carbon steel); Stainless steel should be cut mechanically or plasma with a large margin as much as possible.

2. Deformation

·Phenomenon: Bending occurs when cutting thin-walled pipe fittings.

·Avoidance: Use low-speed band saws or manual saws to reduce heat input and mechanical stress.

3. Mixed samples

·Phenomenon: The sample label falls off or becomes confused after cutting.

·Avoidance: Implement dual labeling (on the sample+on the container bag) and strictly follow the principle of "labeling first, then cutting".

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8. Safety precautions

1. Hot work: Flame cutting must obtain a hot work permit and be equipped with a fire extinguisher.

2. Fixation: Before cutting, the pipe fittings/flanges must be firmly clamped on the vise or cutting machine to prevent them from falling and injuring people.

3. Sharp edge treatment: The edges of the cut sample blank are sharp and must be chamfered or polished in a timely manner to prevent scratches.

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Attachment: Sample Record Representation Example