CN103521946A - High-strength austenitic stainless steel submerged-arc welding wire - Google Patents

Abstract

The invention provides a high-strength austenitic stainless steel submerged-arc welding wire and belongs to the technical field of welding wires. Chemical components of the stainless steel welding wire comprise, by mass, C<=0.025%, Si<=1.00%, Mn<=2.50%, P<=0.020%, S<=0.010%, 12.00-14.00% of Ni, 18.00-20.00% of Cr, 2.00-3.00% of Mo, 0.05-0.10% of N, Nb<=0.150% and the balance iron. High-temperature ferrite delta in cast-condition austenitic stainless steel is 8-15%. By means of the welding wire, the problem that a device is poor in weld line mechanical property when the device runs at high temperature for a long time is solved. The welding wire can be mainly used for welding materials for energy industry, chemical industry and the like at high temperature and under high pressure.

Description

A kind of high strength austenitic stainless steel buried arc welding wire

Technical field

The present invention proposes a kind of high strength austenitic stainless steel buried arc welding wire, belong to welding wire technology field.This welding wire can solve equipment and at high temperature move for a long time the not enough problem of weld properties.Welding wire of the present invention mainly can be for the welding of material under the high-temperature and high-pressure conditions such as the energy, chemical industry.

Background technology

Austenitic stainless steel is widely used in the fields such as oil, chemical industry, aerospace and the energy owing to all having good plasticity and toughness, cold and hot working performance and resistance to local corrosion performance under high temperature and extremely low temperature.As the construction of nuclear power station just need to adopt a large amount of austenitic stainless steels.The at present domestic nuclear power station building is most of is pressurized-water reactor nuclear power plant, and in its heap, temperature is up to 350 ℃, and this has just proposed more and more higher requirement to the high temperature strength of material.The material adopting is at present mainly control nitrogen type austenitic stainless steel, and such steel has the advantages that intensity is high.If will there is the not enough problem of tensile strength by welding point while adopting conventional ER309L welding wire when such steel grade of welding.If Welded Joints is heat-treated, its undercapacity problem will be more outstanding, is therefore necessary to develop a kind of high strength solder wire material, makes the rear joint performance of its welding be not less than or be better than mother metal, has high tensile strength.

Summary of the invention

The object of the present invention is to provide a kind of high strength austenitic stainless steel buried arc welding wire, belong to welding wire technology field.This welding wire can solve the not enough problem of long-term operation weld properties under material presurized water reactor environment.Welding wire of the present invention mainly can be for the welding of critical component in presurized water reactor nuclear island.

Technical scheme of the present invention is, a kind of high strength austenitic stainless steel buried arc welding wire, and its composition percentage by weight is:

C≤0.025%；

Si≤1.00%；

Mn≤2.50%；

P≤0.020%；

S≤0.010%；

Ni?12.00~14.00%；

Cr?18.00~20.00%；

Mo?2.00~3.00%；

N?0.05~0.10%；

Nb?≤0.15%；

Surplus is iron; And the high temperature ferrite δ content in as-cast austenitic stainless steel is 8 ~ 15%.

 

Determine the reasons are as follows of above-mentioned chemical composition:

Carbon: carbon can increase the low temperature intensity of alloy by solution strengthening, but carbon content is too high, carbide can be separated out and cause grain boundary corrosion performance and cryogenic property to reduce at austenite grain boundary, therefore carbon content maximum is preferably to 0.025%;

Nickel: nickel is strong austenite former, increase the stability that nickel content contributes to improve austenite structure, but nickel is precious metal raw material, too high levels can cause material price high, in addition high nickel content is unfavorable for the raising of material at low temperature intensity, is therefore preferably 12～14%.

Chromium: chromium is ferrite former, can obviously increase the decay resistance of alloy, improves the nitrogen solubility in austenitic stainless steel, obtains high intensity.But chromium too high levels, can cause ferrite content in austenite to increase, and is therefore preferably 18.00～20.00%;

Molybdenum: molybdenum is ferrite former, in austenitic stainless steel, add the pitting resistance that molybdenum can improve austenitic stainless steel, by solution strengthening, can improve its intensity, not too much containing adding in the steel grade of molybdenum in welding, in this patent, molybdenum content is controlled as being less than 2.00 ~ 3.00%;

Manganese: increase manganese content can improve the solid solubility of nitrogen element in austenitic stainless steel, but manganese too high levels, can cause producing martensite in austenitic stainless steel, therefore manganese content is preferably and is less than 2.50%;

Nitrogen: nitrogen, as strong austenite former, can obviously improve the elevated temperature strength of austenitic stainless steel on the one hand by solution strengthening, nitrogen and niobium interact on the other hand, can more obviously improve material at high temperature intensity; But nitrogen content is too high, can cause a large amount of nitride to be separated out, can reduce again Toughness and the decay resistance of material, be therefore preferably 0.05～0.10%;

Niobium: except there being the effect of solution strengthening, also can forming tiny second-phase in molten steel with the carbon nitrogen of rare earth element, austenitic stainless steel, thereby for solidifying of molten steel provides forming core particle, make the grain refinement of as-cast austenitic stainless steel.And Nb can with austenitic stainless steel in carbon nitrogen in conjunction with and avoided the reduction of its intergranular corrosion resistance performance.

Silicon: the deoxidier in steelmaking process, its content is inevitable;

Sulphur, phosphorus: the impurity element in alloy smelting process;

By balance nickel chromium equivalent forming element, it is 8 ~ 15% that austenitic stainless steel as cast condition high temperature ferrite δ content is controlled, in order to guarantee the stability of austenite structure in material on the one hand, in welding wire, contain on the other hand a certain amount of ferrite, can make impurity element S, P solid solution in ferritic structure, thereby avoid segregation at crystal boundary, avoided occurring in deposited process fire check and intercrystalline corrosion phenomenon.

 

Concrete, the present invention improves the elevated temperature strength of austenitic stainless steel welding wire for submerged-arc welding according to niobium and nitrogen complex intensifying, carrying the high-intensity while, taken into account the room-temperature property of deposited metal, by rationally determining the content of nickel equivalent forming element Ni, Mn, N, C and chromium equivalent forming element Cr, Si, Mo, the high temperature ferrite content in control austenitic stainless steel guarantees tensile strength, intercrystalline corrosion and the joint quality of welding point.

Proposed for the above reasons austenitic stainless steel buried arc welding wire composition of the present invention, welding wire of the present invention welding point after using has excellent elevated temperature strength, can be used for the welding of presurized water reactor in-pile component.。

The present invention adopts the conventional stainless steel mode of production, being that intermediate frequency furnace or vacuum are molten adds corresponding refining equipment furnace mode and smelts, nitrogen alloying adopts bottom blowing N Gas Alloying or adds nitrogen alloy, in 950-1230 ℃ of temperature range, forge or rolling, within the scope of 1050-1110 ℃, carry out solution heat treatment, pickling to drawing, then obtains corresponding product after bright annealing by too much.

The specific embodiment

The present invention will be further described by the following examples.

Welding wire chemical composition of the present invention and welding point tensile strength are listed in respectively in table 1 and table 2, and austenitic stainless steel wlding welding point of the present invention has excellent elevated temperature strength, can be for using welding or the reparation of high temperature downforce tankage.

Test is prepared through identical production technology with four kinds of welding wires, gage of wire is 2.5mm, the supporting SJ601H that is welded as, welding base metal is 316L(N), welding condition is: arc voltage 28V, welding current is 400A, and speed of welding is 300mm/min, and postwelding has been measured mechanical property and the decay resistance of deposited metal.Wherein decay resistance is according to sulfuric acid-copper sulphate standard in GB4334-2000, and three kinds of welding wires are all without intercrystalline corrosion tendency, in Table 2.

Table 1 embodiment and comparative example standard analysis

(unit: percentage by weight %, surplus is iron and inevitable impurity element)

Table 2 embodiment and comparative example mechanical property and corrosive nature

Claims (3)

1. a high strength austenitic stainless steel buried arc welding wire, is characterized in that chemical composition and mass percentage content thereof are:

C≤0.025%；

Si≤1.00%；

Mn≤2.50%；

P≤0.020%；

S≤0.010%；

Ni?12.00~14.00%；

Cr?18.00~20.00%；

Mo?2.00~3.00%；

N?0.05~0.10%；

Nb?≤0.15%；

Surplus is iron; And the high temperature ferrite δ content in as-cast austenitic stainless steel is 8 ~ 15%.

2. high strength austenitic stainless steel buried arc welding wire as claimed in claim 1, is characterized in that comprising 0.05 ~ 0.10% nitrogen ,≤0.15% Nb, and the compound interpolation of these two kinds of elements can strengthen deposited metal tensile strength at high temperature.

3. high strength austenitic stainless steel buried arc welding wire as claimed in claim 1, is characterized in that the high temperature ferrite δ content in as-cast austenitic stainless steel is 8 ~ 15%.