外文翻译--船舶焊接

1、Welding is to ensure that the ship of the ship and the strength of the key. This paper describes the ship in the welding of several common reasons for the shortcomings and propose preventive measures.Welding is to ensure that the ship of the ship and the strength of the key is to ensure that the key

2、 to the quality of the ship, is to ensure the safety of ships navigating and operating an important condition for. If there is a welding defect, it may cause structural faults, leakage, or even cause the ship sank. According to the ship brittle fracture accident investigation showed that 40 percent

3、of brittle fracture from the accident was the beginning of the weld defects. Ships in the township in shipbuilding, ship the welding quality is particularly prominent. In the inspection of ships in the process of welding the test is particularly important. Therefore, should the early detection of de

4、fects, the welding defects restricted to a certain extent, to ensure navigational safety. Many types of ship welding defects, according to their different positions, the defects can be divided into external and internal defects. Defects have pores, slag, welding cracks, lack of penetration, not fusi

5、on, weld and shape of Dimension are not met, the biting edge, of welding, such as arc pit.first stomatal pore stomatal pore means that the welding, bubble bath in the solidification of the failed escape the hole formed. The main reason there have stomata: groove edge of dirty, water, oil and Xiuji;

6、electrode or not provisions of curing flux, solder or rust-core skin degeneration, such as spalling. In addition, low-hydrogen welding electrode, the arc is too long, welding too fast; submerged arc welding voltage too high, are easily generated in the process of welding stomata. Because the presenc

7、e of porosity so that the seam of effective cross-section decreased, too large pores will reduce the strength of welds, the destruction of the weld metal density. Prevention is to have a stoma: choose the right welding current And welding speed and groove edge to clean up water, oil and Xiuji. Stric

8、tly in accordance with the regulations custody, clearing and curing welding materials. Not to use degenerate electrode, when the skin degeneration drug discovery electrode, spalling or welding core corrosion, should strictly control the use of. SAW, should use the appropriate welding process paramet

9、ers, particularly the plate automatic welding, welding speed should be as small as possible more.Sendcent, slagSlag is the residue of the weld slag. Weld slag will also reduce the intensity and density. A slag is the main reason for Weld aerobic cutting edge of gas or carbon arc shaver residual slag

10、; groove angle or welding current is too small, too fast or welding. Acid in the use of electrode, the current is too small or because of improper transport of a "paste residue" to use alkaline electrode, the arc is too long or because of incorrect polarity will cause the slag. A SAW back

11、cover, from welding wire center, but also easy to slag formation. Prevention Slag produced the measures are: select the right groove size, to clean up groove edge, choose the right welding current and welding speed, and transport of the swing should be appropriate. Multi-welding, should be carefully

12、 observed groove on both sides of melting, each layer must be welded to clean up welding slag. Back cover welding slag should be thoroughly removed, SAW attention should be paid to prevent the solder side.Third, bite Weld left edge of the Depression, known as the biting edge. A biting edge because t

13、he welding current is too large, Yun of the speed and arc welding rod stretched too long or inappropriate angle. SAW welding speed too fast or welder orbit causes of inequality, will cause the melting of welding to a certain depth, and filled with metal also failed to fill the resulting biting edge.

14、 Reduce the biting edge of the base metal joint cross-section of work, thereby resulting in the biting edge of stress concentration, it was important to the structure or structure of the dynamic load, is generally not allowed to bite While there, or to bite-depth limit. Bite-prevention approach is:

15、Choose the right of the welding current and transport practices, the attention of control at any time arc welding rod angle and length; SAW process parameters to be appropriate, with special attention to welding speed should not be too high, welding machine to track formation.Fourth, lack of penetra

16、tion, no fusionWelding, the joints were not fully root penetration of the phenomenon, known as the lack of penetration in the welding pieces of metal and weld seam or a partial layer of penetration phenomenon, known as Fusion did not. Lack of penetration or fusion is a more serious flaw, since lack

17、of penetration or fusion, Weld will appear intermittent or mutation, weld strength greatly reduced, or even cause cracks. Therefore, in the hull of the important parts of the structure does not allow existence of lack of penetration, the situation is not fusion. Lack of penetration and fusion is not

18、 the cause of the welding assembly space or slope argument Of small, blunt-thick, too much electrode diameter, the current is too small, too fast and too long arc, and so on. Weldment groove surface oxide film, oil, and so did not remove clean, or when it flows in the welding of metal slag hinder th

19、e transport of the fusion or improper practices, the arc in the groove while partial and other reasons, will not cause the edge fusion. Prevent the lack of penetration or fusion approach is the right size selected groove, a reasonable choice of welding current and speed, groove and the surface of sk

20、in to remove oil pollution clean; back cover welding-roots thoroughly, and transport of the swing should be appropriate, pay close attention to slope I fusion on both sides of the situation.fifth, welding cracksWelding Crack is a very serious shortcomings. More from the destruction of the cracks, in

21、 the process of welding to take all necessary measures to prevent the emergence of crack in the welding used various methods to check for cracks. Found a crack, should be removed, and then to repair.Welding crack a hot crack, crack cold. Weld metal from liquid to solid in the crystallization process

22、 known as the crack of crack, its characteristic is that immediately after the welding, and more in the center seam along the seam length of the distribution. Heat cracks the surface throughout most of the gap, showing of color, slightly crack the end of round. A hot crack in the weld pool because t

23、here are low melting point impurities (such as FeS, etc.). As a result of these impurities low melting point, crystal solidified the latest, after the solidification of plastic and intensity is very low. Because This, in the structure of binding stress enough the outside world and the solidification

24、 of the weld metal contraction, the pool of low melting point of these impurities in the solidification process was started, or shortly after being opened coagulation, resulting in cracks between the crystal. Welding electrode, and pieces of sulphur, copper and other impurities in a long time, but a

25、lso easy to produce thermal cracks. Prevent hot crack the measures are as follows: 1 to strictly control the welding process parameters, slow down the cooling rate, to increase weld shape factor, as far as possible, using small current multi-channel multi-welding, in order to avoid weld cracks Centr

26、e and the other is seriously The implementation of a point of order, select a reasonable welding process, welding to reduce stress.Weld metal in the cooling process or cooling, the base metal or in the base metal and weld the junction of the fusion line known as the cold crack crack. Such cracks are

27、 likely to arise immediately after the welding is also possible in a few hours after welding, a few days or even longer before there. Cold crack the main reason for: 1) the role of heat cycle, the heat-affected zone generated Hardened organizations, 2) a weld in the excessive proliferation of hydrog

28、en, and has a concentration of the conditions 3) joint bear Binding a greater stress. PreventThe cold crack measures are: 1) choice of low-hydrogen electrode, in the weld to reduce the spread of the content of hydrogen, 2) strictly abide by the welding materials (electrode, Flux) custody, baking, us

29、e the system, guard against exposed to moisture, 3) carefully cleaning up slope I edge of the oil pollution, water and Xiuji, to reduce the sources of hydrogen, 4) According to material grades of carbon equivalent, component thickness, the environment, such as welding, a reasonable choice of the wel

30、ding process parameters and energy lines, such as welding before preheating, solder After the cold ease, taking multi-channel multi-welding, a certain level of control temperature, 5) after the heat emergency Treatment to dehydrogenase, to eliminate the stress and temper hardened organizations, to i

31、mprove joint toughness; 6) the reasonable use of welding procedures, the use of sub-retreat law, such as welding, and welding to reduce stress.sixth, other flawsWelding is also common to a number of welding, arc welding pit and on the external dimensions and shape of the defect. A welding of the mai

32、n reasons is the uneven distribution of transport, resulting pool temperature is too high, the liquid metal solidified slowly falling, thus formed on the surface of the weld metal aneurysm. Li, Yang welding, the use of too much current and arc welding, but also likely to be of welding. Hang generate

33、d arc is put out the reasons for the arc of time is too short, or welding suddenly interrupted or when the current welding plate too much, and so on. Welding seam surface appearance of influence, and easy to create folders surface Java; arc pits and cracks are often accompanied pores, seriously weak

34、ened welding strength. Prevent welding of the main measures to strictly control the pool temperature, Li, Yang welding, welding current ratio should be 10-15 per cent of small-welding, the use of alkaline electrode, should be used short arc welding, and maintain uniformity of transport. Hang prevent

35、 arc is the main measures in hand to arc welding, welding rod should stay for a short period of time or for several of the ring shipped.Some shortcomings of the existence of the safety of ships navigating is very dangerous, once discovered defects should be promptly amended. The porosity of the amen

36、dments, particularly for internal pores, to confirm location, application of wind spade or carbon-arc-shaver clear all the porosity deficiencies and to a corresponding groove, and then carry out welding; the slag, the lack of penetration, Fusion is not the defect, but also have to use the same metho

37、d of removing defects, and then in accordance with the regulations for welding. For crack, should be carefully examined before the crack, crack and the end of The depth, and then eliminate defects. Wind shovel used to eliminate defects, cracks, should first crack at both ends of the drill hole only

38、to prevent the extension of crack. Bored at 8 12 mm by bit, the depth should be more than crack depth 2 3 mm. Carbon arc gas planing to eliminate cracks, they should first crack at both ends of a routing, until the crack eliminated, then the whole crack Paochu. No matter what method to eliminate def

39、ects cracks, it should be a corresponding groove, in accordance with the regulations for welding.Weld defect that the attention should be paid: 1) Welding defects, should adopt the small current, do not swing, multi-multi-channel welding, used to prohibit the current Welding 2) of the rigid structur

40、e of the Welding , In addition to the first layer and the final layer of welding, welding can be carried out under heat after hammering. Each floor from the arc welding and arc should try to stagger 3) require preheating of the material, the work environment at temperatures below 0 , should take cor

41、responding measures preheating, 4) the requirements of the welding of heat treatment , In heat treatment Defects before the amendment; 5) Grade D, E-class high-strength steel and structural steel welding defects, by hand Arc Welding Bushi, the line of control energy should be used welding method. Ea

42、ch time welding defects should be completed, not half-way stop. Preheat temperature and the temperature layer should be maintained at above 60 . 6) the elimination of defects in welds of welding, and not allowed back in the water under pressure circumstances; 7) revised the seam, the seam should be

43、asked to re-examine the testing, found that over again if allowed to limit the deficiencies , Should be re-amended, until qualified. Welding may make no more than the number provided for repairing. 船舶焊接是保证船舶密性和强度的关键。本文详细介绍了船舶焊接中几种常见的缺陷原因并提出防止措施。 船舶焊接是保证船舶密性和强度的关键，是保证船舶质量的关键，是保证船舶安全航行和作业的重要条件。如果焊接存在着

44、缺陷，就有可能造成结构断裂、渗漏，甚至引起船舶沉没。据对船舶脆断事故调查表明，40%脆断事故是从焊缝缺陷处开始的。在乡镇船舶造船中，船舶的焊接质量问题尤为突出。在对船舶进行检验的过程中，对焊缝的检验尤为重要。因此，应及早发现缺陷，把焊接缺陷限制在一定范围内，以确保航行安全。 船舶焊接缺陷种类很多，按其位置不同，可分为外部缺陷和内部缺陷。常见缺陷有气孔、夹渣、焊接裂纹、未焊透、未熔合、焊缝外形尺寸和形状不符合要求、咬边、焊瘤、弧坑等。一、气孔 气孔是指在焊接时，熔池中的气泡在凝固时未能逸出而形成的空穴。产生气孔的主要原因有：坡口边缘不清洁，有水份、油污和锈迹；焊条或焊剂未按规定进行焙烘，焊芯锈蚀

45、或药皮变质、剥落等。此外，低氢型焊条焊接时，电弧过长，焊接速度过快；埋弧自动焊电压过高等，都易在焊接过程中产生气孔。由于气孔的存在，使焊缝的有效截面减小，过大的气孔会降低焊缝的强度，破坏焊缝金属的致密性。预防产生气孔的办法是：选择合适的焊接电流和焊接速度，认真清理坡口边缘水份、油污和锈迹。严格按规定保管、清理和焙烘焊接材料。不使用变质焊条，当发现焊条药皮变质、剥落或焊芯锈蚀时，应严格控制使用范围。埋弧焊时，应选用合适的焊接工艺参数，特别是薄板自动焊，焊接速度应尽可能小些。二、夹渣 夹渣就是残留在焊缝中的熔渣。夹渣也会降低焊缝的强度和致密性。产生夹渣的原因主要是焊缝边缘有氧割或碳弧气刨残留的熔渣

46、；坡口角度或焊接电流太小，或焊接速度过快。在使用酸性焊条时，由于电流太小或运条不当形成“糊渣”；使用碱性焊条时，由于电弧过长或极性不正确也会造成夹渣。进行埋弧焊封底时，焊丝偏离焊缝中心，也易形成夹渣。防止产生夹渣的措施是：正确选取坡口尺寸，认真清理坡口边缘，选用合适的焊接电流和焊接速度，运条摆动要适当。多层焊时，应仔细观察坡口两侧熔化情况，每一焊层都要认真清理焊渣。封底焊渣应彻底清除，埋弧焊要注意防止焊偏。三、咬边 焊缝边缘留下的凹陷，称为咬边。产生咬边的原因是由于焊接电流过大、运条速度快、电弧拉得太长或焊条角度不当等。埋弧焊的焊接速度过快或焊机轨道不平等原因，都会造成焊件被熔化去一定深度，而

47、填充金属又未能及时填满而造成咬边。咬边减小了母材接头的工作截面，从而在咬边处造成应力集中，故在重要的结构或受动载荷结构中，一般是不允许咬边存在的，或到咬边深度有所限制。防止产生咬边的办法是：选择合适的焊接电流和运条手法，随时注意控制焊条角度和电弧长度；埋弧焊工艺参数要合适，特别要注意焊接速度不宜过高，焊机轨道要平整。 四、未焊透、未熔合 焊接时，接头根部未完全熔透的现象，称为未焊透；在焊件与焊缝金属或焊缝层间有局部未熔透现象，称为未熔合。未焊透或未熔合是一种比较严重的缺陷，由于未焊透或未熔合，焊缝会出现间断或突变，焊缝强度大大降低，甚至引起裂纹。因此，在船体的重要结构部分均不允许存在未焊透、未

48、熔合的情况。未焊透和未熔合的产生原因是焊件装配间隙或坡口角度太小、钝边太厚、焊条直径太大、电流过小、速度太快及电弧过长等。焊件坡口表面氧化膜、油污等没有清除干净，或在焊接时该处流入熔渣妨碍了金属之间的熔合或运条手法不当，电弧偏在坡口一边等原因，都会造成边缘不熔合。防止未焊透或未熔合的方法是正确选取坡口尺寸，合理选用焊接电流和速度，坡口表面氧化皮和油污要清除干净；封底焊清根要彻底，运条摆动要适当，密切注意坡口两侧的熔合情况。五、焊接裂纹 焊接裂纹是一种非常严重的缺陷。结构的破坏多从裂纹处开始，在焊接过程中要采取一切必要的措施防止出现裂纹，在焊接后要采用各种方法检查有无裂纹。一经发现裂纹，应彻底清除，然后给予修补。 焊接裂纹有热裂纹、冷裂纹。焊缝金属由液态到固态的结晶过程中产生的裂纹称为热裂纹，其特征是焊后立即可见，且多发生在焊缝中心，沿焊缝长度方向分