CN104668880A - Bearing steel welding repairing method - Google Patents

Abstract

The invention provides a bearing steel welding repairing method. The method comprises the steps of 1, performing the shielded metal arc welding method; 2, selecting a nickel-based welding rod EZNi-1(Z308) or ferro-nickel alloy welding rod EZNiFe-1(Z408) as the welding material; 3, preheating to be 100 to 150 DEG C or stopping preheating before welding; 4, welding with small wire energy through a narrow welding channel; 5, performing short section welding, discontinuous welding, dispersed welding and hammering a weld joint immediately after welding and other measures; 6, performing sectional welding in the welding direction from the closed crack tail end to the crack opening end during repairing the crack; 7, performing the embedded lump welding repairing method, namely, removing the crack dense part or the part with relatively large welding filling quantity, embedding a low carbon steel plate or other materials with high performance, and changing the distribution position of the weld joint; 8, performing the cutting silk welding method for the welding groove surface, namely, drilling and tapping the groove surface of a base material, pinching a low-carbon-steel screw, and welding with the screw as the center. With the adoption of the method, the obtained weld joint is high in quality and less in defect; the work reliability is high, the operability is high, the welding is stable, and the good weld joint can be obtained.

Description

Hold steel welding repair method

Technical field

The present invention relates to Welding Repair Technology field, be specifically related to one and hold steel welding repair method.

Background technology

Be utilize solder technology for REPAIR WELDING method, repairing a kind of working forms of the part lost efficacy, is be referred to as repair welding for repair welding part defect; For recovering part geometry shape and size, or become built-up welding when making its surface acquisition have the fused metal of property.REPAIR WELDING method has very consequence in plant maintenance, and application is very extensive, and therefore Welding Repair Technology technique is even more important for for plant maintenance.

Chemical composition (mass fraction) % of QT600-3

Material

C

Mn

Si

S

P

Mg

QT600－3

3.56～3.85

0.49～0.70

1.83～2.56

0.016～0.045

0.035～0.058

0.041～0.067

The mechanical property of QT600-3

Material	Rm(MPa)	ReL(MPa)	A(％)	HBS	Main metallographic structure
						QT600—3	≧600	370	3	190～270	Ferrite+pearlite

Conventional cast iron method mainly adopts

Cast iron carbon content is high, impurity is many, and has that plasticity is low, weldability is poor, to characteristics such as cooling velocity are responsive, easily occur white structure and crack after soldering.For improving the quality of welding repair of cast iron part, following methods can be taked.

1. hot weld method

Before weldering by whole workpiece or local preheating to 600 ~ 700 DEG C, be not less than 400 DEG C in process of patch weld, postwelding slowly cools to room temperature.Adopt hot weld method can effectively reduce the temperature difference of welding point, thus reduce stress, the plasticity of foundry goods can also be improved simultaneously, prevent white structure and crackle.

Conventional welding method is gas welding and SMAW.Cast iron torch welding rods fabricated is commonly used in gas welding, and as HS401 or HS402, adapted solder flux CJ201, to remove oxide.Gas welding pre-heating mean is suitable for the middle-size and small-size thin-walled parts of repair welding.SMAW selects cast-iron core electrode for cast iron Z248 or cast iron electrode with steel core Z208, and this method is mainly used in the cast iron part of repair welding thickness comparatively large (being greater than 10mm).

2. cold welding method

The method does not carry out preheating to workpiece before weldering, or preheat temperature is no more than 300 DEG C.Conventional SMAW carries out cold welding of cast iron.According to the requirement of cast iron part, can select different electrode for cast irons, as repair welding, the non-machined surface of Gray Cast Iron Parts selects Z100 welding rod, Zll6 or Z117 welding rod selected by repair welding high-strength gray cast iron and spheroidal graphite cast-iron part.

Summary of the invention

In order to solve above-mentioned prior art Problems existing, one is the object of the present invention is to provide to hold steel welding repair method, adopt the weldquality of the inventive method gained high, defect is few, this technological design is new reasonable, and functional reliability is high, and operability is high, welding process is stablized, and can obtain good weld seam.

The process characteristic of cast iron welding:

The welding material that the welding procedure that the cold welding welding procedure of cast iron is different is selected is different.

Cold welding of cast iron technique does not carry out preheating before generally welding, when environment temperature is lower or welding is restrained larger, can preheating 100 ~ 150 DEG C before weldering, and often to adopt special welding material and necessary technological measure during cold welding of cast iron.

Welding material during cast iron welding is selected:

Cold welding of cast iron generally adopts heterogeneous sea welding welding material, and namely weld seam chemical composition and matrix constituent are not identical, comprises base steel, Ni-based and copper base three class welding material.As base steel welding rod EZV (Z116, Z117), EZFe-Fe), nickel-base welding rod EZNi-1 (Z308), EZNiFe-1 (Z408), copper base welding rod EZNiCu-1 (Z508).

The weld hardness of nickel-base welding rod is low, and incomplete fusion zone white structure is thin, and in interrupted distribution, color and the cast iron mother metal of Ni-based weld seam are close, uses relatively more extensive, but adopts nickel-base welding rod production cost high.EZNi-1 (Z308) welding rod is pure nickel core wire, graphite-based cover, and weld metal has certain intensity and plasticity, and incomplete fusion zone chill width is only 0.05mm, and postwelding can carry out machining, is mainly used in the welding on machining surface.EZNiFe-1 (Z408) welding rod is dilval core wire, graphite-based cover, and weld metal cracking resistance is better than pure nickel and nickel-copper electrode, and incomplete fusion zone width is 0.1mm, and weld metal tensile strength is high.The metal chemical composition mechanical property of EZNi-1 (Z308) and EZNiFe-1 (Z408) nickel-base welding rod.

For reaching above object, the present invention adopts following technical scheme:

One holds steel welding repair method, comprises the steps:

(1) welding rod arc welding method is adopted;

(2) nickel-base welding rod EZNi-1 (Z308) or dilval welding rod EZNiFe-1 (Z408) selected by welding material;

(3) weld preheating 100 ~ 150 DEG C or not preheating;

(4) adopt little heat input, string(er) bead welding operation, reduce dilution rate, reduce incomplete fusion zone chill width;

(5) take the measure such as hammering weld seam immediately of short section of weldering, discontinuous welding, dispersion weldering and postwelding, reduce welding stress;

(6) select rational welding direction and order, grasp by the large position of rigidity to the little position welding principle of rigidity, during repair crack, welding direction is carry out segmentation welding from closed crack-tip to the openend of crackle;

(7) use insert repair welding method, namely in the intensive place of crackle or the welding larger position of loading, this position is removed, and is bumped into low carbon steel plate or the good material of other welding performances, change weld seam distributing position;

(8) use studding method at welding groove surface, be exactly boring, tapping on mother metal groove face, mild steel screw is screwed into, weld centered by screw, prevent weld seam from peeling off from mother metal, and improve the ability of the load that withstands shocks, be used for the repair welding of thick large ironcasting.

In sum, adopt the weldquality of the inventive method gained high, defect is few, and this technological design is new reasonable, and functional reliability is high, and operability is high, and welding process is stablized, and can obtain good weld seam.

Detailed description of the invention

Below in conjunction with specific embodiment, the present invention is described in further detail.

One of the present invention holds steel welding repair method, comprises the steps:

(1) welding rod arc welding method is adopted;

(2) nickel-base welding rod EZNi-1 (Z308) or dilval welding rod EZNiFe-1 (Z408) selected by welding material;

(3) weld preheating 100 ~ 150 DEG C or not preheating;

(4) adopt little heat input, string(er) bead welding operation, reduce dilution rate, reduce incomplete fusion zone chill width;

(5) take the measure such as hammering weld seam immediately of short section of weldering, discontinuous welding, dispersion weldering and postwelding, reduce welding stress;

(6) select rational welding direction and order, grasp by the large position of rigidity to the little position welding principle of rigidity, during repair crack, welding direction is carry out segmentation welding from closed crack-tip to the openend of crackle;

(7) use insert repair welding method, namely in the intensive place of crackle or the welding larger position of loading, this position is removed, and is bumped into low carbon steel plate or the good material of other welding performances, change weld seam distributing position;

(8) use studding method at welding groove surface, be exactly boring, tapping on mother metal groove face, mild steel screw is screwed into, weld centered by screw, prevent weld seam from peeling off from mother metal, and improve the ability of the load that withstands shocks, be used for the repair welding of thick large ironcasting.

Claims (1)

1. hold a steel welding repair method, it is characterized in that: comprise the steps:

(1) welding rod arc welding method is adopted;

(2) nickel-base welding rod EZNi-1 (Z308) or dilval welding rod EZNiFe-1 (Z408) selected by welding material;

(3) weld preheating 100 ~ 150 DEG C or not preheating;

(4) adopt little heat input, string(er) bead welding operation, reduce dilution rate, reduce incomplete fusion zone chill width;

(5) take the measure such as hammering weld seam immediately of short section of weldering, discontinuous welding, dispersion weldering and postwelding, reduce welding stress;

(6) select rational welding direction and order, grasp by the large position of rigidity to the little position welding principle of rigidity, during repair crack, welding direction is carry out segmentation welding from closed crack-tip to the openend of crackle;

(7) use insert repair welding method, namely in the intensive place of crackle or the welding larger position of loading, this position is removed, and is bumped into low carbon steel plate or the good material of other welding performances, change weld seam distributing position;

(8) use studding method at welding groove surface, be exactly boring, tapping on mother metal groove face, mild steel screw is screwed into, weld centered by screw, prevent weld seam from peeling off from mother metal, and improve the ability of the load that withstands shocks, be used for the repair welding of thick large ironcasting.