CN103602915B - High carbon and chromium duplex stainless steel - Google Patents

Abstract

The present invention relates to duplex stainless steel, especially a kind of duplex stainless steel and production technique thereof containing high-carbon and high chromium element.Stainless steel of the present invention by weight percentage, its chemical composition is as follows: 0.20-0.35%C, 22-26%Cr, 10-14%Ni, 2-5%Mo, 1-5%Cu, 0.5-4%V, 0.5-5%W, S≤0.015%, P≤0.015%, other impurity element≤1%, surplus is Fe.Invention increases stainless carbon content, improve alloy strength and hardness, add wear resisting property; In alloy except conventional Cr, Ni and Mo element, also with the addition of Cu, W and V element simultaneously, under ensureing that duplex stainless steel has enough corrosion resistance nature conditions, substantially increase tensile strength and the hardness of alloy.

Description

High carbon and chromium duplex stainless steel

Technical field

The present invention relates to duplex stainless steel, especially a kind of duplex stainless steel and production technique thereof containing high-carbon and high chromium element.

Background technology

Along with the development of modern industrial technology, require more and more higher, particularly in the industry that the corrodibility such as oil, chemical industry, boats and ships are stronger to the over-all properties of material.The austenitic stainless steel of early stage multiplex rich nickel is as the material worked in corrosive atmosphere.Practice shows, duplex stainless steel is more anti-corrosion than austenitic steel, and has good comprehensive mechanical property and welding property.In recent years, duplex stainless steel is studied mainly on low-carbon (LC) (being generally 0.01% ~ 0.08%C) basis.But low carbon dual-phase stainless steel, in actual production, needs to carry out carbonization treatment thus adds production difficulty and cost.As everyone knows, carbon improves one of effective, the most most economical element of alloy strength, but up to the present, about the report of high carbon dual-phase stainless steel is fewer.The people such as ChristofMessne have used the duplex stainless steel containing 0.2% carbon when studying the affecting of rolling parameter alloy surfaceness, but do not relate to the structure and properties of material itself.Therefore, a series of research has been carried out to high carbon and chromium duplex stainless steel herein, analyzed the structure and properties of high carbon dual-phase stainless steel, for this kind of alloy is studied further, provided effective foundation and guidance.

Summary of the invention

For the problems referred to above, the present invention proposes a kind of high carbon and chromium duplex stainless steel and production technique thereof, draw materials in actual production conveniently, can production cost be reduced, increase work efficiency.

High carbon and chromium duplex stainless steel of the present invention, by weight percentage, this stainless chemical composition is as follows: 0.20-0.35%C, 22-26%Cr, 10-14%Ni, 2-5%Mo, 1-5%Cu, 0.5-4%V, 0.5-5%W, S≤0.015%, P≤0.015%, other impurity element≤1%, surplus is Fe.

In the present invention, carbon content is 0.2-0.35%, C is effective austenite former.After adding higher carbon element, it can form alloy carbide with the alloying element such as chromium, vanadium and tungsten and improve alloy strength and hardness, increases wear resisting property.Normal smelting technique in addition, because the carbon content of ordinary scrap steel is all below 0.3%, in production process, there is not carburetting, so can ensure that carbon content is within application claims scope.Because the present invention itself requires high carbon content, common melting can obtain the carbon content of needs, so in actual production, alloy without the need to falling through carbonization treatment, low production cost and difficulty.

In the present invention, chrome content is 22-26%, Cr is topmost element in stainless steel, and the increase of chromium element can significantly improve the erosion resistance particularly resistance to pitting attack performance of alloy.But when chromium content is more than 27%, compound between easy precipitating metal, causes the thermoplasticity of alloy and welding property to reduce.In order to make high carbon dual-phase stainless steel have good over-all properties, in the present invention, the add-on of chromium is 22-26%.

Nickel expands austenitic area element, and higher nickel content, can make austenite content in steel increase.In the present invention, nickel content is 10-14%, can improve Alloy Anti high temperature oxidation and corrosion resistance nature, plays stable austenite and acts on mutually.When nickel content too much or very little time, all can not obtain balanced two-phase structure, what cause obtaining duplex stainless steel should have performance.

In the present invention containing molybdenum amount be 2-5%, Mo and Cr element the same be ferrite former, and significantly can improve the corrosion resistance nature of duplex stainless steel, particularly resistance to pitting attack performance.But when molybdenum content is too many, σ phase or the χ phase that can separate out rich chrome molybdenum cause alloy component degradation.

In the present invention, copper content is 1-5%, Cu is austenite former, can improve the solidity to corrosion of alloy in sour environment.When stainless steel of the present invention is 400-500 DEG C of timeliness, Cu Rich Phase Precipitation, can strengthen age hardening.The maximum Precipitation Temperature that copper can reduce σ phase is added in the duplex stainless steel of tungstenic.

In the present invention, tungstenic amount is 0.5-5%, W is ferrite former.Carrying on heavy alloyed corrosion resistance nature, the effect of tungsten is very similar to molybdenum.When part tungsten replaces molybdenum, the impelling strength of alloy can also be increased.In Gao Ge, molybdenum alloy, too much tungsten can increase the precipitation of intermetallic compound, therefore generally≤5%.

In the present invention, vanadiumcontent is 0.5-4%, V is ferrite former, plays Grain refinement, can form stabilizer pole and highly dispersed carbide and intermetallic compound, thus put forward heavy alloyed hot strength and thermostability.When content of vanadium is more than 4%, low-alloyed thermoplasticity can be fallen.

Test of long duration through contriver is determined, by weight percentage, this stainless chemical composition is as follows: 0.25%C, 26%Cr, 13%Ni, 3%Mo, 2.5%Cu, 2%V, 3%W, S≤0.015%, P≤0.015%, other impurity element≤1%, and surplus is Fe.

Produce stainless technique of the present invention, concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1550-1650 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1150 DEG C-1200 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1050-1150 DEG C by rolling;

(4) steel plate after rolling is heated to 1150-1300 DEG C by solution treatment, and quench to obtain after insulation 20-60min product.

The high carbon and chromium duplex stainless steel of proportioning of the present invention, because alloying element kind and content are all more, for increasing solid solution degree and obtaining more balanced austenite phase and ferritic phase tissue.Determine after lot of experiments, best solid solution temperature is 1150-1300 DEG C, shrend or oil quenching.In this temperature range, can ensure that carbide dissolves as far as possible, ferrite and austenitic ratio can be ensured again.As temperature is too low, can not ensure that carbide dissolves as far as possible, the higher and coarse grains of the too high then ferrite content of temperature.

In sum, the present invention has following beneficial effect:

1, add the carbon content in duplex stainless steel, suitably put forward high nickel content, and adopt higher solid solution temperature, improve alloy strength and hardness, add wear resisting property, and in actual production, get starting material convenient, reduce production cost and difficulty;

2, in alloy except conventional Cr, Ni and Mo element, also with the addition of Cu, W and V element simultaneously, under ensureing that duplex stainless steel has enough corrosion resistance nature conditions, substantially increase tensile strength and the hardness of alloy.

Accompanying drawing explanation

Fig. 1 be high carbon and chromium duplex stainless steel of the present invention organize metallograph;

In figure: 1 is austenite phase; 2 is ferritic phase.

Embodiment

Embodiment 1

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.35%C, 23%Cr, 12%Ni, 3.5%Mo, 4%Cu, 0.5%V, 2.7%W, 0.015%S, 0.010%P, 1% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1550 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1200 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1100 DEG C by rolling;

(4) steel plate after rolling is heated to 1150 DEG C by solution treatment, and quench to obtain after insulation 60min product.Embodiment 2

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.20%C, 25%Cr, 10%Ni, 2%Mo, 2%Cu, 3.1%V, 0.5%W, 0.015%S, 0.010%P, 1% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1570 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1150 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1150 DEG C by rolling;

(4) steel plate after rolling is heated to 1300 DEG C by solution treatment, and quench to obtain after insulation 20min product.Embodiment 3

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.25%C, 24%Cr, 14%Ni, 3%Mo, 5%Cu, 2.2%V, 5%W, 0.005%S, 0.015%P, 0.5% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1600 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1170 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1050 DEG C by rolling;

(4) steel plate after rolling is heated to 1200 DEG C by solution treatment, and quench to obtain after insulation 40min product.Embodiment 4

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.3%C, 26%Cr, 13%Ni, 4%Mo, 1%Cu, 1.3%V, 3.9%W, 0.010%S, 0.005%P, 1% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1650 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1160 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1070 DEG C by rolling;

(4) steel plate after rolling is heated to 1170 DEG C by solution treatment, and quench to obtain after insulation 50min product.Embodiment 5

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.27%C, 22%Cr, 11%Ni, 5%Mo, 3%Cu, 4%V, 1.6%W, 0.015%S, 0.010%P, 1% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1630 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1190 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1130 DEG C by rolling;

(4) steel plate after rolling is heated to 1250 DEG C by solution treatment, and quench to obtain after insulation 30min product.Embodiment 6

A kind of high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.25%C, 26%Cr, 13%Ni, 3%Mo, 2.5%Cu, 2%V, 3%W, 0.015%S, 0.015%P, 1% other impurity elements, and surplus is Fe.

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1650 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1200 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1150 DEG C by rolling;

(4) steel plate after rolling is heated to 1250 DEG C by solution treatment, and quench to obtain after insulation 30min product.Comparative example

Two-phase stainless steel sample obtained by above-described embodiment 1-6 and other duplex stainless steels are carried out resistance to pitting performance and Mechanics Performance Testing.Resistance to pitting performance is according to GB GB4334.7, and measure in the 6%FeCl3+0.05MHCl solution of 35 DEG C, mechanical property measures according to GB GB/T10623-2008, and it the results are shown in Table 1.

Table 1

Specimen types

Corrosion rate (g(m 2·h） -1）

Tensile strength (MPa)

Unit elongation (%)

Hardness (HRC)

Embodiment 1	0.95	918	24	29
					Embodiment 2	0.73	905	24	28
Embodiment 3	0.56	878	23	27
					Embodiment 4	0.43	892	24	27
Embodiment 5	1.12	928	26	29
					Embodiment 6	0.42	913	25	28
SAF2205	1.52	680	25	20
					SAF2507	0.35	797	29	24

As can be seen from Table 1, the resistance to pitting performance of duplex stainless steel of the present invention is between SAF2205 and SAF2507 stainless steel.The tensile strength intensity of duplex stainless steel of the present invention and hardness are obviously high than SAF2205 and SAF2507 stainless steel and keep good unit elongation.

Claims (1)

1. a high carbon and chromium duplex stainless steel, by weight percentage, this stainless chemical composition is as follows: 0.3%C, 26%Cr, 13%Ni, 4%Mo, 1%Cu, 1.3%V, 3.9%W, 0.010%S, 0.005%P, 1% other impurity elements, and surplus is Fe;

Its preparation technology's concrete steps are as follows:

(1) raw material is cast into ingot casting according to after said ratio mixed melting in 1650 DEG C by melting casting;

(2) above-mentioned ingot casting is forged into steel plate at 1160 DEG C by forging;

(3) steel plate after forging is rolled into steel plate at 1070 DEG C by rolling;

(4) steel plate after rolling is heated to 1170 DEG C by solution treatment, and quench to obtain after insulation 50min product.