Module 1 Radiographic Examination 射线探伤

1. Module 1 Radiographic Examination 射线探伤

2. 学习目标 • 通过本课的学习，了解射线探伤、超声波探伤、磁粉探伤、渗透探伤等焊缝质量的无损检测方法。使学生掌握相关的专业词汇，提高学生阅读、理解科技英语的能力。

3. New Words • radiography /reIdII/ n. 射线照相法 • inclusion /Inklu:n/ n. 夹渣 • void /vI/ n. 空洞，孔洞，缩孔 • radioactive /reIdIEJAktIv/ adj. 放射性的 • develop /I/ v. 冲洗 • discontinuity/dIskntInjJ:ItI/ n. 缺陷, 不连续性 • generator /enreIt/ n. 发电机, 发生器 • cathode /kWd/ n. 阴极 • anode /nJd/ n. 阳极, 正极 • vacuum/vkjJm/ n. 真空

4. New Words • decay /dIkeI/ n. 衰败，衰退 • cobalt /kbC:lt/ n. 钴 • iridium /IrIdIm/ n. [化]铱 • thulium /Wju:lIm/ n. [化] 铥 • cesium /si:zjm/ n. [化]铯 • uranium /jJreInIm/n. 铀 • vault /v:lt/ n. 保管库，拱顶 • capsule /kpsju:l/ n. 瓶帽, 太空舱 • emulsion /Imln/ n. 乳化剂 • fixer /fIks/ n. 定影剂

5. Phrases

6. Module 1 Radiographic Examination • Radiography is a nondestructive examinationmethod that uses invisible, x-ray, or gamma radiation to examine the interior of materials①. • 射线照相法是一种使用不可见的X射线或γ射线检测材料内部缺陷的无损探伤法。

7. Radiographic examination (RT) gives a permanent film record of defects that is relatively easy to interpret. • 射线探伤具有可永久保存的缺陷的底片，并且缺陷比较直观。

8. Although this is a slow and expensive method of nondestructive examination, it is a positive method for detecting porosity, inclusions, cracks, and voids in the interior of castings, welds, and other structures. • 虽然这是一种检测速度慢且费用较大的无损探伤方法，但它是一种检验铸件、焊件和其他结构件的内部气孔、夹渣、裂纹和缩孔的有效方法。

9. X-rays, generated by electron bombardment of tungsten, and gamma rays emitted by radioactive elements are penetrating radiation whose intensity is modified by passage through a material②. • 由钨的电子轰击所产生的X射线和由放射性元素所放射的γ射线都是可穿透性的射线，它们的强度会由于穿过材料而改变。

10. The amount of energy absorbed by a material depends on its thickness and density. • 材料所吸收的能量的多少取决于材料的厚度和密度，

11. Thus a thinner part will absorb less energy than a thick part, and a heavy dense metal, such as steel, will absorb more energy than a light metalsuch as aluminum. • 因此薄件将比厚件吸收的能量少，大密度的金属（例如钢）将比轻金属（例如铝）吸收更多的能量。

12. Energy not absorbed by the material will cause exposure of the radiographic film. These areas will be dark when the film is developed. • 没有被材料吸收的能量将使射线底片曝光，从而当胶片被冲洗后，这些区域将发黑；

13. Areas of the film exposed to less energy remain lighter. Therefore, areas of the material where the thickness has been changed by discontinuities, such as porosity or cracks, will appear as dark outlines on the film③. • 而胶片上被少量能量曝光的区域，顔色较浅。因此，在材料中被缺陷（如气孔或裂纹）改变厚度的区域将在底片上显示出黑色轮廓。

14. Inclusions of low density, such as slag, will appear as dark areas on the film, while inclusions of high density, such as tungsten, will appear as light areas. • 在胶片上密度小的夹渣（例如焊渣）将呈现出黑色的区域，而密度大的夹渣（例如钨）将呈现出亮的区域。

15. All discontinuities are detected by viewing shape and variations in the density of the processed film. • 通过观察冲洗过的底片上的形状和密度的变化，那么所有的缺陷都会被检测出来。

16. The x-ray or gamma-ray source and penetrameter are placed above the piece to be radiographed and the film is placed on the opposite side of the part (Figure 5-1). • X或γ射线源和像质计被放置在被检验的工件上面，底片被放置在工件的背面，如图5-1所示。

17. X-rays are produced by electrons hitting a tungsten target inside an x-ray tube. In addition to the x-ray tube, the apparatus consists of a high-voltage generator with necessary controls④. • X射线是通过电子轰击X射线管内的钨靶产生的。除了X光管外，射线机还包括高压发生器和控制器。

18. X-rays are produced when a high-speed stream of electrons collides with a piece of tungsten. The electrons are produced in the x-ray tube by a hot cathode. • 当高速的电子流轰击钨片时将产生X射线，电子是由在X光管中的热阴极材料产生的。

19. They are accelerated towards the anode by means of an electron gun in the vacuum of the x-ray tube. • 在真空的X光管中，通过电子枪，电子被加速射向阳极。

20. The anode is a piece of tungsten, and when the electrons hit it, x-rays are produced which are directed through a window to the part being inspected. • 阳极是一钨片，当电子撞击它时，X射线就产生了，并且X射线将直接通过窗口射到被检的工件上。

22. Gamma rays are produced by radioactive decay of certain radioisotopes. • γ射线是由某种放射性同位素的衰减而产生的。 • The radioisotopes normally used are cobalt-60, iridium-192, thulium-170, and cesium-137. • 常用的放射性同位素有钴-60、铱-192、铥-170和铯-137。

23. These isotopes are contained in a lead or spent uranium vault or capsule to provide safe handling⑤. • 这些同位素能被铅屏蔽或者采用铀贮藏库来提供安全防护。 • They have a relatively short half-life and the strength of the radiation decreases with time. • 它们的半衰期较短，并且随着时间的延长，射线强度将减弱。

24. Isotopes must be handled in such a way that radiographic sources can be positioned and yet produce minimum radiation hazards to operating personnel⑥. • 同位素必须在能够放置X射线源，而且对操作人员辐射危害最小的方式下进行处理。

25. Remote handling equipment is employed when the radioactive source is drawn from the shielded contained to the material to be radiographed. • 当放射源从保护区到被检材料距离较远时，那么就要使用遥控器。 • In the United States a license from the U.S. Department of Energy is required for use of radioisotopes. • 在美国，使用放射性同位素，必须取得美国能源部的许可证。

26. The radiation intensity or output from an x-ray machine or from radioisotope sources will vary. Common materials such as concrete and steel are used to house the x-ray machine and protect the operator from exposure. • 来自于X射线机或放射性同位素的射线强度会发生改变。普通的材料如混凝土和钢被用于制作X射线机的防护房，用以保护操作者，以防止其受到辐射。

27. The thickness of the shielding enclosure walls should be sufficient to reduce exposure in all occupied areas to a minimum value. • 保护围墙的厚度应足够厚，使在所有能照射到的区域将辐射减少到最小值。

28. If the work is too large or too heavy to be brought into the shielded room, special precautions such as lead-lined booths and portable screens are used to protect personnel. • 如果工件太大或太重而无法放进防护房时，那么就需要采取特殊的预防措施如铅衬里的工作间和轻便的屏幕来保护操作人员。

29. In the field, radiography protection is usually obtained from distance alone, since radiation intensity decreases as distance increases. • 在野外，射线的防护通常是采用距离防护措施，因为射线强度将随距离的增加而减弱。

30. Penetrameters are used to determine the sensitivity of the radiograph. They are made of the same material that is being inspected and are usually 2% of the thickness of the part being tested. • 像质计被用于确定X光照片的灵敏度。它们由与被检测的工件相同的材料制成，而且通常是被检工件厚度的2%。

31. Therefore, if the penetrameter can be seen clearly on the radiograph, any change in thickness of the part (2% or more) will be seen clearly. • 因此，如果在X光照片中，像质计清晰可见，那么工件厚度上的任何变化（2%以上）都能被清晰地看见。

32. Radiographic film consists of a transparent plastic sheet coated with a photographic emulsion. When x-rays strike the emulsion, an image is produced. • 射线胶片是由一层涂有乳化剂的透明的塑料薄膜组成。当X射线撞击乳化剂时，影像就会形成。

33. The image is made visible and permanent by afilm-processing operation. Most processing equipment consists of tanks that contain a developer, a fixer, and rinse solutions. • 通过暗室处理，这个影像则是可见的并且是永久的。大多数的暗室处理设备都是由各种槽（盛装显影剂、定影剂和冲洗液的槽）所组成。

34. Film-processing operations are just as critical as the film exposure. Unsatisfactory radiographs can sometimes be attributed to errors in the processing technique or from mishandling of materials. • 暗室处理是和底片曝光一样关键的过程。X光照片质量差，有时是由于错误的操作技术或材料使用不当所致。

35. Radiography is one of the most popular nondestructive examination methods for locating subsurface defects. • 射线照相法是应用最广泛的、用于内部缺陷检验的无损探伤方法之一。

36. It is used for examination of weldments in all types of materials: steel, aluminum, magnesium, and so on. Radiography is used in the pipeline industry to ensure proper weld quality. • 它可用于检验所有种类的材料的焊件：钢、铝、镁等等。射线照相法被用于管道工业，确保焊接质量合格。

37. Most indications will show up as dark regions against the light background of the sound weld. Radiographs should be examined with a film illuminator providing a strong light source. • 大多数的显示都呈现出完好焊缝的浅色背景与黑色区域相映衬。X光照片使用能提供强烈光源的观片灯进行检验。

38. It is essential that qualified personnel conduct X-ray interpretations since false interpretation of radiographs causes a loss of time and money • 质检人员对X光照片进行评片是重要的，因为对X光照片的错误判定，将造成时间和金钱的损失。

39. Radiographs for reference are extremely helpful in securing correct interpretations. Consulting the specification involved for standards of acceptability and qualification of equipment and operators. • 用X光照片作参考，对正确的判定是极其有帮助的。查阅的参考资料包括质量标准、设备和操作人员说明书。

40. 谢谢