CN103521887A - Welding technology of 45 steel and 35 CrMo cast steel - Google Patents

Abstract

The invention discloses a welding technology of 45 steel and 35 CrMo cast steel. The technology includes the following steps that firstly, preheating is performed, a plate core and a plate piece are placed into an annealing furnace for being preheated to the temperature of 300 DEG C at the temperature rising speed of 40-60 DEG C per hour, heat preservation is performed for one hour, the plate core and the plate piece are taken out of the furnace and assembled, gas is used for continuous heating, and therefore the welding process is constantly kept at the preheating temperature of 200 DEG C and 250 DEG C; secondly, according to a welding manner, an H08Mn2SiA welding wire is adopted, and the argon-rich CO2 gas of 80% of Ar+20% of CO2 is used for protecting welding; thirdly, according to welding parameters, the diameter of the welding wire is 1.2mm, the welding currents are 190-240A, the welding voltage is 28-32V, the interlayer temperature is 200-250 DEG C, and the gas flow is 15-20L/min. Multilayer and multi-bead welding is adopted, welding beads are mutually overlapped, and the width of an overlapped welding joint is no smaller than 1/3 that of a welding joint. Meanwhile, each time one layer is welded, an air chipper is used for hammering the welding joint to relieve stress, and after welding, stress relief heat treatment is performed in the furnace. According to the welding technology of the 45 steel and the 35 CrMo cast steel, restraint stress can be greatly reduced, and therefore cracks are effectively prevented.

Description

The welding procedure of a kind of 45 steel and 35CrMo cast steel

Technical field

The present invention relates to the welding field of the different steel of steel, the welding procedure of especially a kind of 45 steel and 35CrMo cast steel.

Background technology

Hammer mill is by motor, to be driven the machinery of main shaft, disk, bearing pin and each hammer High Rotation Speed, and hammer is contained on the bearing pin between each disk in hinge mode, and tup impulsive force makes solid crushing, and disk bears the shock loading of pulsation.It is by 35 CrMo dish cores, form with 10 45 steel plate disc weldings, the thick 80mm of disc, dish core and the disc mutually boss of weldering place are 80 mm, weld shape is circumferential weld, large due to thickness of slab, structural rigidity is very large, and postwelding produces very large restriction tention because weld seam shrinks, and easily causes crackle, therefore should reduce as far as possible weld size, reduce stress.Due to the 178mm only of distance between disc, so the welding first of disc and dish core is double groove, and all the other can only be single grooves.

35 CrMo steel have sizable tendency of hardenability, the quenching structure of postwelding is crisp hard high carbon martensite, sensitiveness to cold crack is large, in addition disc and dish core boss thick 80 mm that are, constraint degree is larger, be prone to larger restraint stress, this easily causes weld affected zone generation embrittlement or cracking.

Summary of the invention

The object of the invention is to propose the welding procedure of a kind of 45 steel and 35CrMo cast steel, it can reduce restraint stress greatly, thereby has effectively controlled the appearance of crackle.

The technical scheme that the present invention solves its technical problem employing is: the welding procedure of 45 steel and 35CrMo cast steel adopts following steps: a. preheating, dish core and disc are put the programming rate with 40～60 ℃/h in annealing furnace and are preheating to 300 ℃, insulation 1h come out of the stove group right, and continue heating and thermal insulation with coal gas, make welding process remain the preheat temperature of 200～250 ℃;

B. welding manner, adopts H08Mn2SiA welding wire, the rich argon CO2 gas shielded arc welding of 80% Ar+ 20% CO2;

C. welding parameter, gage of wire is 1.2mm, and welding current is 190 ~ 240A, and weldingvoltage is 28 ~ 32V, 200 ~ 250 ℃ of interlayer temperatures, gas flow, 15 ~ 20L * min ^-1, adopt multi-pass welding, welding bead overlaps each other, overlapping weld seam is no less than 1/ 3 of weld width, be often soldered simultaneously one deck with pneumatic shovel hammering weld seam to eliminate stress; Postwelding enters stove and does to eliminate stress heat treatment.

The invention has the beneficial effects as follows: adopt multiple tracks multilayer welding, utilize later layer, rear one weld seam to front one deck, front one weld seam drawing effect hammering weld seam, can crystal grain thinning, improve intensity and the toughness of weld seam.

The specific embodiment

Below in conjunction with in concrete enforcement, the present invention will be further described: the welding procedure of 45 steel and 35CrMo cast steel adopts following steps: a. preheating, dish core and disc are put the programming rate with 40～60 ℃/h in annealing furnace and are preheating to 300 ℃, insulation 1h come out of the stove group right, and continue heating and thermal insulation with coal gas, make welding process remain the preheat temperature of 200～250 ℃;

B. welding manner, adopts H08Mn2SiA welding wire, the rich argon CO2 gas shielded arc welding of 80% Ar+ 20% CO2;

C. welding parameter, gage of wire is 1.2mm, and welding current is 190 ~ 240A, and weldingvoltage is 28 ~ 32V, 200 ~ 250 ℃ of interlayer temperatures, gas flow, 15 ~ 20L * min ^-1, adopt multi-pass welding, welding bead overlaps each other, overlapping weld seam is no less than 1/ 3 of weld width, be often soldered simultaneously one deck with pneumatic shovel hammering weld seam to eliminate stress; Postwelding enters stove and does to eliminate stress heat treatment.

1.1 weld preheating

35CrMo steel, because Ceq=0.74% is higher, has sizable hardenability, thereby in the overheated zone of welding heat affected zone, is easy to produce hard crisp high carbon martensite.Cooling velocity is larger, and the high carbon martensite of generation the more, crisp firmly also just more serious.For reducing the embrittlement of overheated zone, from reducing tendency of hardenability, employing adds large-line energy should be favourable, but because the tendency of hardenability of 35CrMo steel is very large, only by adding large-line energy, be difficult to avoid martensitic formation, but it is austenitic overheated and improved austenitic stability to have increased on the contrary, impels and forms thick martensite, makes the embrittlement of overheated zone more serious.Therefore, in welding process, need to take little heat input, take the measures such as preheating slow cooling and after heat simultaneously.Because adopt little heat input to reduce high-temperature residence time, avoid the overheated of austenite crystal to grow up, increased austenite uneven components, thereby reduced austenitic stability, and adopt the measures such as preheating and slow cooling to reduce cooling velocity simultaneously, improved like this performance of overheated zone.Because the preheat temperature of 35CrMo steel is 200～250 ℃, consider on-the-spot actual conditions, preheat temperature is decided to be to 220～250 ℃, interlayer temperature is not less than 200 ℃.

1.2 welding method

Compare with manual metal-arc welding, MAG soldering set has the features such as heat is concentrated, deposition efficiency is high, dilution rate is low, welding deformation is little, crack resistance is good.Rich argon CO2 gas shielded arc welding can obviously improve the transition of molten drop simultaneously; there is the feature such as splash less, appearance of weld is attractive in appearance; simultaneously due to 178 mm only of the distance between disc; during manual metal-arc welding, welding rod cannot stretch into, therefore this welding has adopted the rich argon CO2 gas shielded arc welding of 80% Ar+ 20% CO2.

1.3 welding material

The tensile strength of 45 steel is 600 M Pa, and the tensile strength of 35CrM o steel is 980 MPa.The wlding adopting according to dissimilar steel welding should with the principle of low-intensity material equal intensities, therefore adopt H08Mn2SiA welding wire, its deposited metal plasticity is better, has certain contraction leeway while making weld seam cooling, can greatly reduce restraint stress, thereby effectively control the appearance of crackle.

2.1 preheating methods and Insulation

Dish core and disc are put the programming rate with 40～60 ℃/h in annealing furnace and are preheating to 300 ℃, and the insulation 1h group of coming out of the stove is right, and continues heating and thermal insulation with coal gas, makes welding process remain the preheat temperature of 200～250 ℃.

2.2 first disc assemblings and welding

First adopts two-sided welding, group to time perpendicularity between assurance dish core and disc, 9 remaining discs will be assembled as benchmark.Put disk disc in horizontal level, make weld seam be horizontal welding.Welding procedure: first weld the thick 25～30mm of a side ring weld seam, the weldering of upset opposite side is full, then remaining part is filled up in upset.

The 2.3 second～ten disc assembling and welding

Due to close together between disc (178mm), can only adopt single-sided welding, take last disc as benchmark group is to next disc, utilize the pin shaft hole of disk to reinforce, then weld; First with the adjustable Bin Caini welding gun of nozzle angle, at the groove back side, weld one deck, then in the welding of groove side, until fill up equal with mother metal.So circulation is assembled remaining disc, welded.

2.4 welding condition

The technological parameter of welding is in Table 1.By the symmetrical welding simultaneously of two welders, adopt multi-pass welding, welding bead overlaps each other, overlapping weld seam is no less than 1/ 3 of weld width, be often soldered simultaneously one deck with pneumatic shovel hammering weld seam to eliminate stress; Postwelding enters stove and does to eliminate stress heat treatment.Heat treating regime is, 40～60 ℃/h of programming rate, and workpiece is heated to 600 ± 20 ℃, and insulation 4h is cooling with stove.

Table one welding condition

Claims (1)

1. the welding procedure of a steel and 35CrMo cast steel, it is characterized in that process using following steps: a. preheating, dish core and disc are put the programming rate with 40～60 ℃/h in annealing furnace and are preheating to 300 ℃, insulation 1h come out of the stove group right, and continue heating and thermal insulation with coal gas, make welding process remain the preheat temperature of 200～250 ℃;

B. welding manner, adopts H08Mn2SiA welding wire, the rich argon CO2 gas shielded arc welding of 80% Ar+ 20% CO2;

C. welding parameter, gage of wire is 1.2mm, and welding current is 190 ~ 240A, and weldingvoltage is 28 ~ 32V, 200 ~ 250 ℃ of interlayer temperatures, gas flow, 15 ~ 20L * min ^-1, adopt multi-pass welding, welding bead overlaps each other, overlapping weld seam is no less than 1/ 3 of weld width, be often soldered simultaneously one deck with pneumatic shovel hammering weld seam to eliminate stress; Postwelding enters stove and does to eliminate stress heat treatment.