外文翻译---低合金结构钢的焊接性分析

外文资料翻译

WELDABILITY ANALYSIS OF Q345 STEEL

LOW STEEL ALLOY STRUCTURE OF WELDABILITY

ANALYSIS

16Mn and 15MnV belong to the low-alloy steel hot rolled steel, these steel prices lower, and has satisfied the mechanical properties and processing performance, first of all to analyze this type of steel welding, welding on two points of typically Bianxian questions: First, due to a variety of welding defects, such types of steel for the main crack; Second, changes in material properties when welding on the type of steel is mainly embrittlement problem.

1. Crack

(1) Thermal crack: hot rolled carbon content generally lower, while the higher manganese content, so they Mn / S comparison, and has good resistance to thermal cracking performance. Normally, the weld hot cracking does not occur, but when the material component failure or serious segregation of carbon, sulfur content higher, Mn / S ratio is low, prone to hot cracking. Manganese in the steel with manganese sulfide sulfur to reduce the harmful effects of sulfur and enhance the performance of steel thermal cracking.

(2) Cold crack: the crack depends on the cold steel, hardened steel, the tendency of the tendency toward hardening just depends on its chemical composition. Hot rolled steel contains a small amount of alloying elements because of its low carbon steel when the carbon equivalent is slightly high er than some, so this low carbon steel hardened tend to be bigger than that, but with the increase of steel strength level, the increase in alloying elements, it The hardening tendency increases should be based on the form and steel fittings to adjust the line thickness of the energy, preheating and post-heat

temperature, to control the heat-affected zone of the cooling rate, while reducing the amount of weld metal hydrogen and other measures to prevent cold cracks.

(3)Reheat cracking: Considerations from the chemical composition of steel, hot rolled steel does not contain as strong carbide forming elements, so again not sensitive to hot cracking, but also by increasing the preheating temperature and post weld heat such measures immediately after to prevent hot cracking.

2. Embrittled

(1)Hot zone embrittlement: hot rolled steel welding near the weld zone is heated to above 100 ℃coarse grain zone, easy to produce grain growth phenomenon is worst in welded joints of plastic parts, often to withstand the stress the role of the damage. To prevent the overheating zone embrittlement measures is to improve the cooling rate, in particular, to improve the stability of austenite within the minimum cooling rate, shorten the residence time in this temperature range, reduce or prevent the emergence of austenite to raise steel impact toughness, but also to prevent the overheating zone coarse-grained brittle, should not be using too much energy input.

(2) Heat should be crisp: the heat should be crisp is the thermal stress during the welding process because the plastic deformation to dislocation multiplication, while nitrogen and carbon atoms induced rapid proliferation of dislocation accumulation area, there should be crisp of heat. 16Mn and 15MnV these two types of steel has got to be brittle tendency of heat, eliminating welding heat should be crisp and effective measures of post-weld annealing.

LOW ALLOY STRUCTURAL STEEL WELDING

1. Welding preparation:

(1) The design of groove type of welding should be avoided not through or partial penetration of the groove, but also to minimize the weld cross-sectional area to reduce the residual stress in joints, it can also reduce