The weldability of 40CrNiMo and GCr15 can experiment research

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[summary] the weldability that studies 40CrNiMo and GCr15 steel through the experiment can, in order to realize practical and new-style patent " railroad pounds pick with fission type " the application in actual production, reduced those who pound pick to make reach use cost. Test result makes clear, through soldering, can obtain admirable 40CrNiMo and GCr15 steel heterogeneous steel solders contact, use fission structure to make pound pick to have practical. One, the overview pounds pick is the important part in car of railroad machinery tamp, belong to wear away easy bad news, basically counted an import in the past, use cost is very high. This task group is in pound pick homebred on the basis that changes research, invented a kind of practical and new-style patent " railroad pounds pick with fission type " . Type of this kind of fission pounds pick to have a lot of advantages, its are main the feature is pick body and pick boots forgings apart, body uses pick 40CrNiMo whole forgings figuration, boots drafts pick use GCrl5 to forging, pass body of pick of solder fetch join and pick boots. The weldability that passes research 40CrNiMo and GCrl5 steel can, make practical and new-style patent technology " railroad pounds pick with fission type " be able to apply go among actual production, reduced those who pound pick to make cost. 2, experiment content 1.

The chemical composition of data of test data test sees a table 1, watch 2 reach a table 3. 2.

Test data heat treatment undertakes moving pledging handling to 40CrNiMo steel, via 850 ℃ oily temper by dipping in water 2h of 600 ℃ temper, its microstructure is shown 1 times like the graph. Undertake undertaking quenching bout fire is handled to GCrl5 steel, in 850 ℃ oily temper by dipping in water 2h of 300 ％ temper, if its microstructure pursues 2 Xin are shown. Solder material microstructure is shown 3 times like the graph. 3.

Solder 40CrNiMo of test of the function after reaching solder and GCrl5 solder belong to heterogeneous steel to solder, from solder the choice of material, welder art make solder of the process carry out the principle with must be abided by certain. Considering circumstance of the job that pound pick, the function test after solder undertakes contact pounds function test and analysis of appearance of fracture surface form soldering only. Because pound pick,concussion load basically bears when the job, solder contact basically is cut stress with fatigue stress generation to destroy. Solder hind has line cut to sample, cut does not have breach to pound sample into standard of 55mm of × of 10mm × 10mm. In JB, 36 3 with concussion experiment machine aspirant travel pounds an experiment. 3, test result and analysis 1.

Solder contact pounds an experiment from the watch 4, watch 5 can see, solder the concussion toughness value that contact pounds toughness to be worth data of test having a competition should be gotten greatly much, demonstrative welding line is in when be pounded load, won't rupture first than metal of mother capable person. 2.

Solder contact metallographic analysis solders the metallographic photograph of contact is shown 4 times like the graph. By the graph 4 can see, the grain that heat of a side of capable person of the mother in graph 4a affects an area to stand by bond is bulkier, advocate if because this one area is soldering,heat,overheat condition is in in the process, make austenite grain produces grown phenomenon, bulky organization gets after refrigeration; Organization of welding line metal did not produce apparent change, bond feature is not apparent. The welding line in graph 4b and organization of hot influence area did not produce apparent change, bond can see a line only. Solder the produces limitation the most easily section in contact is bond, but the limitation as a result of experiment condition, the feature of bond cannot observe further, because this also is affected,arrive to solder to this the judgement of contact quality. Affect an area to judge from welding line metal and heat of mother capable person only, this solders contact does not have big weld defects, this from solder value of contact concussion toughness also can see. 3.

Solder fracture surface of concussion of analysis of appearance of form of contact concussion fracture surface basically is formed by 3 area, if pursue 5 shown fiber regions, radiative area and cut a lip. Be in above all sample (without breach sample) crackle source is formed near the root place buy that rupture; Subsequently crackle enters stable and patulous phase, form the fiber division of dark gray; Enter later break certain patulous level quickly, form radiative division of Bai Liang. The feature of radiative area is to have radiative variety, radiative direction and crackle are patulous direction is parallel, hang down business the contour line at crackle forward position, go against point to crackle source; The line of have a common boundary of fiber area and radiative area is indicating crackle by slow and patulous do not stabilize to what expand quickly patulous change. Can radiating in the fracture surface below some circumstances area and cut a 2 fiber area appears again between the area. If the tenacity of material is enough good, radiative area can disappear completely, put in fiber area to mix only cut a lip. Can see in fiber area concave and convex the appearance of body of gray fiber state of tropism of more remarkable in the right way, it is corresponding taller tenacity is worth. By the graph 6 can see, fracture surface basically is fracture surface of nest of pliable but strong, but expand in crackle stable state level, existing brittleness ruptures. Graph 6b is mouth of smooth fragile absolutely of crystal boundary of rock candy shape, this is one kind is appearing hardly the crystal boundary that happens below circumstances of any microcosmic plasticity metabolic is fragile break, edge of its fracture surface is very lively, on brilliant face very flowing, break appearance of degree of lip-rounding for typical rock candy written complaint, it is to absorb a the most fragile energy is few kind to rupture form. The formation of this kind of fracture surface, on one hand because the intensity inside brilliant is higher not easy slippage, meet an emergency is easy center at crystal boundary; On the other hand, crystal boundary is brought about as a result of all sorts of reasons again fragile change, cannot bear plasticity meet an emergency and craze. Because brittleness photograph film exists on crystal boundary,this is those who cause is fragile change, welding line metal is comprised by austenite stainless steel, because the carbide on crystal boundary precipitates and stainless steel of austenite of this kind of chromic nickel is caused rupture, at this moment precipitation photograph film is not successive certainly, enclothe crystal boundary area to make an appointment with 50 ％ when it, can make crystal boundary ruptures below outside force action when. Because solder,this kind ruptures also may be the hydrogen in the process is fragile bring about " hydrogen is sent come off " . This shows, solder contact basically is tenacity ruptures, explain further thereby, GCr15 and 40CrNiMo solder contact is had solder goodly quality. 4, epilogue (1) GCr15 and 40CrNiMo solder result of contact concussion test makes clear, solder contact has good concussion toughness, can satisfy the place that pound pick to accept the demand that pounds load. (2) solders from GCr15 and 40CrNiMo apparent weld defects cannot see in contact metallographic organization, solder contact solders quality is good, what in making clear experiment process, make solder craft and operating rules are reasonable and feasible. (3) from solder receive appearance of form of contact fracture surface the analysis is knowable, GCr15 and 40CrNiMo solder contact ruptures means basically is tenacity ruptures. CNC Milling CNC Machining