Superaustenitic material
A superaustenitic material is provided for use in chemical plant construction or in oilfield or gas field technology. The material resists corrosion, in particular corrosion in mediums with high chloride concentrations and sulfuric acid.
1. A precipitation-free superaustenitic material comprising an alloy with the following alloy elements in % by weight:
Elements
Carbon (C)
0.01-0.25
Silicon (Si)
<0.5
Manganese (Mn)
3.0-8.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Iron (Fe)
residual
Chromium (Cr)
23.0-30.0
Molybdenum (Mo)
2.0-4.0
Nickel (Ni)
10.0-16.0
Vanadium (V)
<0.5
Tungsten (W)
<0.5
Copper (Cu)
<0.5
Cobalt (Co)
<5.0
Titanium (Ti)
<0.1
Aluminum (Al)
<0.2
Niobium (Nb)
<0.1
Boron (B)
<0.01
Nitrogen (N)
0.50-0.90
balance Iron (Fe) and inevitable impurities;
wherein the precipitation-free superaustenitic material is cold-formed with sufficient deformation to yield a tensile strength Rm of at least 1100 MPa, a notched-bar toughness KV of at least 80 J, and Rm multiplied by KV is greater than 100,000 MPa-J.
2. The precipitation-free superaustenitic material according to claim 1 , wherein the alloy comprises the following elements in % by weight:
Elements
Carbon (C)
0.01-0.20
Silicon (Si)
<0.5
Manganese (Mn)
4.0-7.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Iron (Fe)
residual
Chromium (Cr)
24.0-28.0
Molybdenum (Mo)
2.5-3.5
Nickel (Ni)
12.0-15.5
Vanadium (V)
<0.3
Tungsten (W)
<0.1
Copper (Cu)
<0.15
Cobalt (Co)
<0.5
Titanium (Ti)
<0.05
Aluminum (Al)
<0.1
Niobium (Nb)
<0.025
Boron (B)
<0.005
Nitrogen (N)
0.52-0.80
balance Iron (Fe) and inevitable impurities;
and Rm multiplied by KV is greater than 200,000 MPa-J.
3. The precipitation-free superaustenitic material according to claim 1 , wherein the alloy comprises the following elements in % by weight:
Elements
Carbon (C)
0.01-0.1
Silicon (Si)
<0.5
Manganese (Mn)
5.0-6.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Iron (Fe)
residual
Chromium (Cr)
26.0-28.0
Molybdenum (Mo)
2.5-3.5
Nickel (Ni)
13.0-15.0
Vanadium (V)
below detection limit
Tungsten (W)
below detection limit
Copper (Cu)
below detection limit
Cobalt (Co)
below detection limit
Titanium (Ti)
below detection limit
Aluminum (Al)
<0.1
Niobium (Nb)
below detection limit
Boron (B)
<0.005
Nitrogen (N)
0.54-0.80
balance Iron (Fe) and inevitable impurities;
and Rm multiplied by KV is greater than 300,000 MPa-J.
4. The precipitation-free superaustenitic material according to claim 1 , wherein the material is produced by a method comprising secondary metallurgical processing of the molten metal, casting into blocks, hot forming immediately afterward, the cold forming, and optional further mechanical processing.
5. The precipitation-free superaustenitic material according to claim 1 , wherein the material has a yield strength R p0.2 in excess of 500 MPA.
6. The precipitation-free superaustenitic material according to claim 1 , wherein the material has a notched bar impact work at room temperature in the longitudinal direction Av in excess of 300 J.
7. The precipitation-free superaustenitic material according to claim 1 , wherein the material is fully austenitic.
8. The precipitation-free superaustenitic material according to claim 1 , wherein the manganese is present at about 3.5% to about 7% by weight of the alloy.
9. The precipitation-free superaustenitic material according to claim 1 , wherein the chromium is present at greater than 25% to about 29% by weight of the alloy.
10. The precipitation-free superaustenitic material according to claim 1 , wherein the molybdenum is present at about 2.3% to about 3.7% by weight of the alloy.
11. The precipitation-free superaustenitic material according to claim 1 , wherein the nickel is present at about 11% to about 15% by weight of the alloy.
12. The precipitation-free superaustenitic material according to claim 1 , wherein the nitrogen is present at about 0.52% to about 0.85% by weight of the alloy.
13. The precipitation-free superaustenitic material according to claim 1 , wherein the cobalt is present at less than about 1% by weight of the alloy.
14. The precipitation-free superaustenitic material according to claim 1 , wherein the copper is present at less than about 0.3% by weight of the alloy.
15. The precipitation-free superaustenitic material according to claim 1 , wherein the tungsten is present at less than about 0.3% by weight of the alloy.
16. The precipitation-free superaustenitic material of claim 1 , wherein the tensile strength Rm is at least 2000 MPa.
17. A precipitation-free superaustenitic material comprising an alloy with the following alloy elements in % by weight:
Elements
Carbon (C) 0.01-0.25
Manganese (Mn) 3.0-8.0
Chromium (Cr) 25.1-30.0
Molybdenum (Mo) 2.0-4.0
Nickel (Ni) 10.0-16.0
Vanadium (V), Tungsten (W), Silicon (Si) and Cobalt (Co) in a combined amount of zero to 2.0
Copper (Cu), Titanium (Ti), Aluminum (Al), Niobium (Nb), Boron (B), Phosphorus (P) and Sulfur(S) in a combined amount of zero to 1.0
Nitrogen (N) 0.50-0.90
balance Iron (Fe) and inevitable impurities;
wherein the precipitation-free superaustenitic material is cold-formed with sufficient deformation to yield a tensile strength Rm of at least 1100 MPa, a notched-bar toughness KV of at least 80 J, and Rm multiplied by KV is greater than 100,000 MPa-J.
18. A method for producing a precipitation-free superaustenitic material, comprising the steps of:
providing an alloy comprising the following elements in % by weight:
Elements
Carbon (C)
0.01-0.25
Silicon (Si)
<0.5
Manganese (Mn)
3.0-8.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Iron (Fe)
residual
Chromium (Cr)
23.0-30.0
Molybdenum (Mo)
2.0-4.0
Nickel (Ni)
10.0-16.0
Vanadium (V)
<0.5
Tungsten (W)
<0.5
Copper (Cu)
<0.5
Cobalt (Co)
<5.0
Titanium (Ti)
<0.1
Aluminum (Al)
<0.2
Niobium (Nb)
<0.1
Boron (B)
<0.01
Nitrogen (N)
0.50-0.90
balance Iron (Fe) and inevitable impurities;
melting the alloy;
subjecting the alloy to secondary metallurgical processing;
casting the alloy into blocks and permitting the blocks to solidify;
immediately after solidifying the blocks, heating and hot forming the blocks; and
cold forming and mechanically processing the blocks;
wherein the cold forming causes sufficient deformation of the precipitation-free superaustenitic material to yield a tensile strength Rm of at least 1100 MPa, a notched-bar toughness KV of at least 80 J, and Rm multiplied by KV is greater than 100,000 MPa-J.
19. The method according to claim 18 ,
wherein the alloy comprises the following elements in % by weight:
Elements
Carbon (C)
0.01-0.20
Silicon (Si)
<0.5
Manganese (Mn)
4.0-7.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Iron (Fe)
residual
Chromium (Cr)
24.0-28.0
Molybdenum (Mo)
2.5-3.5
Nickel (Ni)
12.0-15.5
Vanadium (V)
<0.3
Tungsten (W)
<0.1
Copper (Cu)
<0.1
Cobalt (Co)
<0.5
Titanium (Ti)
<0.05
Aluminum (Al)
<0.1
Niobium (Nb)
<0.025
Boron (B)
<0.005
Nitrogen (N)
0.52-0.80
balance Iron (Fe) and inevitable impurities;
and Rm multiplied by KV is greater than 200,000 MPa-J.
20. The method according to claim 18 , wherein the alloy comprises the following elements in % by weight:
Elements
Carbon (C)
0.01-0.10
Silicon (Si)
<0.5
Manganese (Mn)
5.0-6.0
Phosphorus (P)
<0.05
Sulfur (S)
<0.005
Chromium (Cr)
26.0-28.0
Molybdenum (Mo)
2.5-3.5
Nickel (Ni)
13.0-15.0
Copper (Cu)
<0.1
Aluminum (Al)
<0.1
Boron (B)
<0.005
Nitrogen (N)
0.54-0.80
balance Iron (Fe) and inevitable impurities;
and Rm multiplied by KV is greater than 300,000 MPa-J.
21. The method according to claim 18 , wherein the hot forming comprises a plurality of sub-steps.
22. The method according to claim 18 , further comprising the steps of:
re-heating the block between the sub-steps, and after the last sub-step, and optionally solution annealing after the last sub-step.
23. The method according to claim 21 , further comprising the step of:
performing the cold forming of the block after the last sub-step and the optional solution annealing, in order to achieve a tensile strength Rm>2000 MPa.