CN102373369A

CN102373369A - Steel for oil and gas transmission pipe fitting

Info

Publication number: CN102373369A
Application number: CN2010102525720A
Authority: CN
Inventors: 马力; 艾福奇; 洪连山
Original assignee: LIAOYANG PETROCHEMICAL MACHINERY DESIGN MANUFACTURING Co Ltd
Current assignee: LIAOYANG PETROCHEMICAL MACHINERY DESIGN MANUFACTURING Co Ltd
Priority date: 2010-08-13
Filing date: 2010-08-13
Publication date: 2012-03-14

Abstract

The invention relates to steel for an oil and gas transmission pipe fitting, specifically to steel for the oil and gas transmission high pressure pipe and the oil and gas transmission high pressure pipe fitting. A purpose of the present invention is to solve the problems of low temperature intolerance and poor H2S corrosion resistance of the steel for the high pressure pipe fitting in the prior art. The steel for the oil and gas transmission pipe fitting is the 10MnVT i NbA steel, and the chemical composition of the steel mainly comprises Fe, and further comprises the following metal elements, by weight, 0.08-0.13% of C, 0.15-0.37% of Si, 1.20-1.50% of Mn, less than or equal to 0.01% of S, less than or equal to 0.015% of P, 0.02-0.06% of V, 0.01-0.03% of Ti, 0.03-0.05% of Nb, and less than or equal to 0.25% of CE. The production process of the steel is performed according to the X60 steel production process technology regulation in the API 5LPSL2 standard. The steel of the present invention has advantages of strong H2S corrosion resistance and strong low temperature resistance.

Description

Transportation pipe spare is used steel

Technical field:

The present invention relates to a kind of oil gas carries pressure piping, pipe fitting to use steel.

Background technology:

That existing H.P.F is widely used with steel is AP I 5LPSL ₂The intensity of X60 steel and plasticity can satisfy the H.P.F requirement in the standard, but not low temperature resistant, anti-H ₂The S corrosive nature is poor, bursting by freezing often occurs or because of the corrosion pipe explosion accident.

Summary of the invention:

Technical problem to be solved by this invention provides a kind of anti-H ₂S corrosion and the strong transportation pipe spare of low temperature tolerance ability are used steel.

Above-mentioned purpose is achieved in that described transportation pipe spare is a 10MnVT i NbA steel with steel; Its chemical constitution is main with Fe, and the per-cent that other metallic element accounts for gross weight is: C 0.08%-0.13%, S i 0.15%-0.37%, Mn 1.20%-1.50%, S≤0.01%, P≤0.015%, V 0.02%-0.06%, T i 0.01%-0.03%, Nb 0.03%-0.05%, C _E≤0.25%.

C _E＝C+S?i/30+Mn/20+Gr/20+MO/15+N?i/60+V/10+Cu/20+5B≤0.25％

Described transportation pipe spare with the working method of steel is, presses the chemical ingredients of 10MnVT i NbA steel, adopts electric furnace+VD stove or converter+VD stove to smelt, and production technique is according to AP I 5LPSL ₂The production technology rules of X60 steel are carried out in the standard.

Advantage of the present invention is: 10MnVT i NbA is the perlitic steel that ferritic adds cementite in metallographic structure.C forms cementite with Fe chemical combination in steel, carbon content is high more in the steel, and cementite area occupied in metallographic structure is also big more, and the purity of steel also improves thereupon, but the plasticity of steel and impelling strength also decrease.It is to make that the ferritic area accounts for more than 85% in its metallographic structure that the C purpose falls in the present invention, is beneficial to low-temperature impact toughness and improves.

S i is a kind of good reductor in molten steel, it and O ₂Chemical combination forms S i O ₂Float over molten steel surface, pull down, play except that O with slag ₂Fluxing effect.

Mn is good deoxidation, sweetening agent in molten steel, and it can eliminate or weaken the red brittleness that sulphur causes, improves the hot workability of steel; The sosoloid that Mn and iron form can improve ferritic intensity; It is again a carbide forming element, and it gets in the cementite, replaces the carbide that the part iron atom forms, and plays the effect of refine pearlite group; Make the matrix of steel obtain to strengthen.Mn is again the principal element that reduces the low temperature brittleness transition temperature in the steel, thereby improves the low-temperature impact toughness of steel.

S, P form low melting component in steel, and respectively with crystal boundary on, they belong to harmful element, content is low more good more in the steel.It is minimum in steel, S, P to be dropped to, and this is anti-H ₂The effective technology measure of S steel.

V forms particle in steel minimum, and fusing point is high, again carbide-the V of stabilizer pole ₄C ₃, in the phase transition process of steel, with V ₄C ₃For the nucleus refinement ferrite crystal grain, and can suppress effectively that crystal boundary moves and grain growth.Thereby can effectively improve the hardening capacity matrix strength and the low-temperature impact toughness of steel.

T i is one of very active metallic element in the chemistry, and it and nitrogen in steel, oxygen, carbon all have extremely strong avidity, and it also is better than iron with the avidity of sulphur.Therefore, it is the effective element of a kind of good reductor and fixed nitrogen, sulphur, under some special conditions, can replace manganese and form titanium sulfide, forms to avoid hot-short iron sulphide.Though titanium is the strong carbide forming element, it does not form double carbide with other element, and it and carbon only form a kind of carbide-T i C.T i C bonding force is very strong, and is extremely stable, be difficult for to decompose, and in steel, only is heated to more than 1000 degree Celsius, the α that could dissolve in sosoloid lentamente mutually with γ mutually in.In phase transition process, be nucleus with T i C, thus refinement ferrite crystal grain, improved the intensity of steel.

The ferro-niobium of steel-making usefulness, actual is the niobium tantalum alloy.They are symbiotic in the mineral deposit, when smelting, are difficult to separate, and ferro-niobium is the coexistence of niobium tantalum.They and carbon, nitrogen, oxygen all have extremely strong avidity, and form accordingly very stable compound with it.Their main effects in steel are the refinement ferrite crystal grains, effectively improve intensity, impelling strength and the creep resisting ability of steel, and can reduce the heat sensitivity and the temper brittleness of steel.

So grade of steel of the present invention is high, carbon content is low, and impelling strength is high, anti-H ₂S corrosion and low temperature tolerance ability are strong; Through test, the room temperature tensile performance is all qualified with " V " notched specimen-48 ℃ ballistic work, is more than 6 times of low-temperature steel impact value in the U.S. ASTM A333-92 standard; And fracture is plasticity; Good welding performance has reached the performance level of Ap15L-2000 standard performance and X60 steel, can satisfy the needs that oil gas is carried H.P.F.

Embodiment:

Described transportation pipe spare is a 10MnVT i NbA steel with steel, and its chemical constitution is main with Fe, and the per-cent that other metallic element accounts for gross weight is: C 0.08% or 0.11% or 0.13%; S i 0.15% or 0.23% or 0.26% or 0.33% or 0.35% or 0.37%; Mn 1.20% or 1.25% or 1.32% or 1.34% or 1.43% or 1.50%; S≤0.01%; P≤0.015%; V 0.02% or 0.03% or 0.05% or 0.06%; T i 0.01% or 0.02% or 0.03%; Nb 0.03% or 0.04 or 0.05%; C _E≤0.25%.

C _E＝C+S?i/30+Mn/20+Gr/20+MO/15+N?i/60+V/10+Cu/20+5B≤0.25％

Claims

1. transportation pipe spare is used steel; Described transportation pipe spare is a 10MnVT i NbA steel with steel; It is characterized in that: chemical constitution is main with Fe, and the per-cent that other metallic element accounts for gross weight is: C 0.08%-0.13%, S i 0.15%-0.37%, Mn 1.20%-1.50%, S≤0.01%, P≤0.015%, V0.02%-0.06%, T i 0.01%-0.03%, Nb 0.03%-0.05%, C _E≤0.25%.