High nitrogen steel is one kind of stainless steel whose nitrogen content exceeds the limit nitrogen content that can be achieved in steel under conventional conditions. According to the different amount of nitrogen added, the following classification is roughly made, that is, the steel with nitrogen content >1% is ultra-high [SCALE STEEL]nitrogen, the steel with nitrogen content 0.3 ~ 0.5% is high nitrogen, and the steel with nitrogen content below this range is nitrogen. The effect of nitrogen in stainless steel is mainly reflected in three aspects: the microstructure, mechanical properties and corrosion resistance of stainless steel. The results show that nitrogen is a very strong element that forms and stabilizes austenite and enlarges the austenite phase region. It can replace part of nickel in stainless steel, reduce the ferrite content in steel, make austenite more stable, prevent the precipitation of harmful intermetallic phases, and even avoid the occurrence of martensite transformation under cold working conditions.
Used to think that nitrogen in steel will be brittle and must be processed to remove elements as, but during the period of 1910 ~ 1930 in nitrogen in steel can improve the strength of the research, and use it to improve the toughness, fatigue strength and corrosion resistance, such as performance, found that the addition of[SCALE STEEL] nitrogen quantity the more the more the performance improving trend, so as to carry out the related research of the amount of the expanded to join.
The biggest reason for interest in nitrogen is that it can substitute nickel. In the 1930s and 1940s, in order to save nickel from wartime supplies in Japan, nitrogen as a substitute for nickel to form austenite phase was paid [SCALE STEEL]attention to. However, until now, how to improve the properties of steel by nitrogen solution and its mechanism are still unknown, which need to be solved urgently.
Mechanical Properties of High Nitrogen Content Stainless Steel:
With the increase of nitrogen element in stainless steel, the hardness, yield strength, tensile strength and fatigue resistance of stainless steel have been significantly improved. The introduction of nitrogen can effectively improve the strength of stainless steel and stabilize the austenite phase, which can be said to kill two birds with one stone. Especially the introduction of nitrogen can significantly improve the yield strength and tensile strength of alloy materials.
Local Area Corrosion Resistance:
There is no doubt that the introduction of nitrogen greatly improves the corrosion resistance of the material. This can be clearly [SCALE STEEL]seen from The calculation formula of The Pitting resistance Equivalent number:
Formula 1: PREN=%Cr+3.3%Mo+16%N
According to the above formula, the pitting corrosion equivalent of stainless steel is mainly determined by the nitrogen content in stainless steel. Its calculation factor reaches 16. Nitrogen content also significantly[SCALE STEEL] changed PREN values. This is just a calculation formula for the PREN value of nitrogenous stainless steel materials. In the high nitrogen stainless steel materials composed of different formulas, the calculation factor of nitrogen element even reaches more than 25.
Because of high strength stainless steel’s excellent matching and corrosion resistance, strong toughness in aerospace, it is widely usded in the field of national economy and people's livelihood application like marine engineering ,energy equipment manufacturing, such as the plane of the main bearing components, fasteners, [SCALE STEEL]satellite gyroscope, ship shell, offshore oil platform, automobile industry, nuclear industry, gear and bearing manufacturing, etc., It is the preferred material for lightweight design, energy saving and emission reduction of future equipment components. As one of the important candidate materials for load-bearing and corrosion-resistant structural parts, how to combine ultra-high strength and toughness with excellent service safety is the key development direction of this kind of steel in the future.
Carnegie Illionois developed the first generation of martensitic precipitation-hardened stainless steel in 1946 to meet the needs of high performance corrosion resistant structural steels for aerospace and Marine engineering. On the basis of Stainless W steel alloy system, Cu and Nb elements were added and Al and Ti elements were removed. American Arm‐ CO Steel Company developed 17-4pH steel in 1948 . Due to its good strength, toughness and corrosion resistance, it is widely used in manufacturing fasteners and engine parts besides landing gear components of F-15 aircraft, but its cold deformation ability is poor. In order to reduce the high temperature δ -ferrite which is unfavorable[SCALE STEEL] to the transverse mechanical properties, a 15-5pH steel [5-7] was developed by reducing the content of Cr and increasing the content of Ni. This steel overcomes the disadvantage of 17-4pH steel in transverse plasticity and toughness, and has been used in the manufacturing of ship and civil aircraft bearing parts. In the early 1960s, Inco invented martensitic aging steel and introduced the concept of martensitic aging strengthening for the development of high strength stainless steel, thus opening the curtain of the development of martensitic aging stainless steel. In 1961, the American company first developed the maraging stainless steel Custom450 containing Mo. Later, Pyromet X-15 and Pyromet X-12 were developed in 1967 and 1973 respectively. During this period, the United States has also developed AM363, In736, PH13-8MO, Unimar CR, etc. Martin et al. [8,9] obtained the invention patents of Custom465 and Custom475 steel in 1997 and 2003 respectively, and applied them in civil aviation aircraft. British developed FV448, 520, 520(B), 520(S) and other high strength stainless steel brands. Germany developed the Ultrafort401 and 402 in 1967 and 1971. In addition to copying and improving American steel grades, the Former Soviet Union independently researched a series of new steel grades. In 2002, QuesTek undertook the pollution prevention project of THE STRATEGIC Environmental Research and Development Program (SERDP) of the U.S. Department of Defense. Through the Material Genome Project, QuesTek designed and developed Ferrium®S53, a new type of ultra-high strength stainless steel for aircraft landing gear , and published [SCALE STEEL]the AMS5922 aerospace standard at the end of 2008. Ferrium®S53 has A strength of about 1,930mpa and fracture toughness (KIC) of 55 MPa·m1/2 or more. It has been added into the MMPDS trunk Material Manual of the United States in 2017, and has been successfully applied to THE A-10 fighter aircraft and T-38 aircraft of the United States. It is the preferred material for the landing gear of the next generation of carrier-based aircraft.
China began to develop high strength stainless steel in the 1970s. In 2002, CIRON and Steel Research Institute designed and developed a new type of ultra-high strength and toughness stainless steel material, which is the ultra-high strength stainless steel USS122G of Cr-Ni-Co-Mo alloy system independently developed by China with independent intellectual property rights. Its strength is more than 1900 MPa and KIC is more than 90 MPa·m1/2 . At present, the material has broken through the key technology related to the preparation of bar with a diameter of 300 mm, and has a wide application prospect in the field of Aerospace equipment manufacturing in China.
Stress Corrosion Cracking of Ultra High Strength Stainless Steel:
According to the failure investigation report of Aircraft parts in The United States, stress corrosion cracking is one of the main forms of [SCALE STEEL]sudden failure accidents occurred in the service of key load-bearing parts of aircraft, and most landing gear is finally broken due to stress corrosion or fatigue crack propagation . At present, stress corrosion occurs not only in aviation, aerospace, energy, chemical and other high-tech industries, but also in almost all commonly used corrosion resistant steel and metal. Therefore, it is of great scientific value and practical significance to analyze the stress corrosion cracking mechanism of ultra-high strength steel and the factors affecting the stress corrosion of ultra-high strength steel.
The corrosion resistance of materials becomes an important factor to limit the stress corrosion cracking of high strength steel, and pitting corrosion is the most common and harmful form of corrosion. Most stress corrosion cracking [SCALE STEEL]originated from pitting pits. In the process of aging treatment, the microstructure of ultra-high strength stainless steel is not uniform due to the precipitated phase from supersaturated martensite matrix, which is the main source of pitting corrosion of ultra-high strength stainless steel. The passivation film near the precipitated phase is weak, and the invasion of Cl- leads to the destruction of the passivation film, and the formation of microbatteries between the precipitated phase and the matrix, so that the matrix is dissolved, the precipitated phase spares off, and pitting corrosion is formed. For example, cr-rich carbides M23C6 and M6C and intermetallic compounds Laves phase equal σ are prone to form cr-poor zone around, resulting in pitting phenomenon. Luo et al.  and Yu Qiang  studied the effect of aging time on the microstructure and electrochemical behavior of 15-5pH ultra-high strength stainless steel by using THREE-DIMENSIONAL atomic probe chromatography. Cu-rich clusters and (Cu,Nb) nanoparticles were observed when aging time was 1-240 min. After long-term aging treatment, the sample surface is more susceptible to Cl- erosion. After aging for 240 min, The Cr content around the [SCALE STEEL]precipitates also decreased, and Cr poor zone was easily formed in these parts. The decrease of Cr/Fe ratio in passivated film leads to the decline of pitting resistance of passivated film. In addition, the continuous precipitation of Cr-rich carbides at grain boundaries reduces the intergranular corrosion resistance of steel. For example, the study  found that AISI 316Ti stainless steel has higher intergranular corrosion resistance than AISI 321 stainless steel, because the precipitation of Ti C reduces the formation of Cr-rich carbides, which is one of the precipitates leading to intergranular corrosion.
As the most important ductile phase in high strength stainless steel, the content, morphology, size and stability of austenite also affect the stress corrosion sensitivity of steel. Under the condition of the same size, morphology and stability, the stress corrosion cracking threshold value (KISCC) increases with the increase of austenite content, and the stress corrosion cracking sensitivity of steel decreases. The reason is that the thin-film austenite structure formed on the martensitic slat boundary improves the toughness of steel and reduces the hydrogen-induced crack growth rate. There are two main reasons for the decrease of crack growth rate. One is: When the crack expands from martensitic matrix to thin-film austenite, either it continues to expand into the austenite or changes the direction of propagation to bypass the austenite structure, it will consume more energy, resulting in the decrease of crack growth rate and the increase of stress corrosion resistance sensitivity. Second: as I mentioned earlier, H in austenitic organization have higher solid solubility, low [SCALE STEEL]partial tendency, and the rate of diffusion of H in austenite is far smaller than in the martensite structure, is beneficial in high strength stainless steel hydrogen trap, results in the decrease of hydrogen embrittlement sensitivity of the crack front, the crack propagation rate reduce, improve the stress corrosion sensitivity. It should be noted that the stability of austenite is also a key parameter determining the stress corrosion sensitivity of steel. After the stress or strain-induced martensitic transformation, the fresh martensite transformed from austenite can not only suppress the crack propagation, but also improve the sensitivity of steel hydrogen embrittance as a new source of hydrogen diffusion.
In conclusion, the strength and toughness, stress corrosion and hydrogen embrittlement sensitivity of steel are affected by the complex multistage and multiphase structure, and the design and preparation of ultra-high strength stainless steel with excellent service performance by traditional trial and error method is difficult, long cycle and high cost. Compared with the trial-and-error method, the rational design method, such as establishing a series of multi-scale analysis models of strength and toughness, stress corrosion properties and hydrogen brittleness, will be more purposeful. The results of simulation analysis can be used to establish the design standard of high strength stainless steel, optimize the morphology, size and content of precipitated phase, martensite and austenite structure in steel, and further combine the multi-scale simulation with the actual material development process, which will greatly reduce the difficulty of material development, reduce the cost and shorten the development cycle.
Ultra High Strength Stainless’ Future Development:
As a metal structure material with excellent strength, toughness and service safety, high strength stainless steel has a broad application prospect in aviation, aerospace, Marine engineering and nuclear industry. In view of the harsh [SCALE STEEL]application environment of this kind of steel, the exploration of a new generation of high-strength stainless steel should not only focus on breaking the bottleneck of matching ultra-high strength and excellent plasticity and toughness, but also take into account the excellent service safety. In the process of alloy design and heat treatment process formulation, the traditional trial-and-error method is gradually transferred to thermal/dynamic assisted alloy design, artificial intelligence mechanical learning and other rational design methods, in order to greatly improve the research and development cycle of new high-strength corrosion resistant alloy and save the research and development cost. The mechanism of strengthening and toughening in high strength stainless steel is still to be further studied, especially the understanding of the precipitation behavior of the second phase and the superposition of the strengthening contribution value. The effect of austenite content, size, morphology and stability on the toughness[SCALE STEEL] of high strength stainless steel has been studied extensively, but no effective mathematical model has been established to quantitatively estimate the contribution of austenite content, size, morphology and stability to the toughness of high strength stainless steel.
In addition, it is urgent to solve the stress corrosion fracture mechanism and hydrogen embrittlement sensitivity of ultra-high [SCALE STEEL]strength stainless steel under complex strengthening system, so as to provide a theoretical basis for the durability design of ultra-high strength stainless steel.
321H stainless steel has good corrosion resistance, especially in oxidizing medium has good corrosion resistance. Because of its good heat resistance and oxidation resistance, it is more used as a heat resistant steel. Comparing with 321 Stainless steel, [SCALE STEEL]321H has higher Carbon content and similar properties with 321 Stainless.
A. 321H Corresponding Brand:
1, GB GB-T standard: digital brand number: S32169, new brand number: 07Cr19Ni11Ti, old brand number: 1Cr18Ni11Ti;
2, American standard: ASTM standard: [SCALE STEEL]S32109, UNS standard: 321H;
3, JIS standard: SUS321HTB;
4, DIN standard: 1.4940,1.4541;
5, European standard EN standard: "X8CrNiTI18-10, X7CrNiTI18-10;
6, NF standard: /;
7, British BS standard: 321S20.
B. 321H Stainless Steel Chemical Composition:
⑴ carbon C: 0.04~0.10⑵ silicon Si: ≤0.75, [SCALE STEEL]⑶ manganese Mn: ≤2.00, ⑷ phosphorus P: ≤0.030, ⑸ sulfur S: ≤0.030,[SCALE STEEL] ⑹ chromium Cr: 17.00 ~ 20.00, ⑺ nickel Ni: 9.00 ~ 13.00, other elements: Ti≥4C~0.60.
C. 321H Stainless Steel Physical Properties:
Density Density (20℃) /kg/dm3:"8.03,, magnetism: none.
D. 321H Stainless Steel Mechanical Properties:
(1) Delivery status: solid solution treatment of bar, solid solution pickling of plate;
⑵ Tensile strength (RM/MPa) 520;
⑶ Elongation strength[SCALE STEEL] (Rp0.2/MPa) : 205;
⑷ Elongation A/% : 40;
⑸ Area shrinkage (Z/%) : 50.
E. 321H Stainless Steel Heat Treatment:
1. Hardness HBW≤ : solution 187, hardness HRB≤ : 90;
2. Heating temperature: 920~1150;
3. Heating method: fast cooling.
321H Stainless Steel’s Application:
321H Stainless Steel is [SCALE STEEL]widely used for boiler superheater, heat exchanger, condenser, catalytic tube, cracking tube device and other steel tubes and fittings.
GS-25CrNiMo4 alloy is one kind of special Cr-Ni-Mo Alloy which is suitable used under the environment with temperature up to 300℃[SCALE STEEL].
Chemical Composition for GS-25CrNiMo4 Alloy:
Ni(％):0.80-1.20 [SCALE STEEL]
Mechanical Property for GS-25CrNiMo4 Alloy:
Proof Strength Rp0.2(MPa):350-400
Tensile Strength Rm(MPa):650-850
Impact Energy KV(J):24
Elongation at Fracture A(%):21
Reduction in Cross [SCALE STEEL]section on Fracture Z(%):43
As-Heat-Treated Conditions:Solution and Aging,Annealing,Ausaging,Q+T,etc
For Moe Infos about GS-25CrNiMo4, pls feel free to contact us.
I. Introduction of 12Ni14 Nickel Alloy Plate
12Ni14 is a boiler pressure vessel steel plate, using the European standard brand, 12Ni14 is a nickel alloy steel plate used in pressure equipment, [SCALE STEEL]the common brand of European standard container plate are: HII/P265GH P275NH P275NL P355GH P355NH P355NH P355NL1 P460NH 16Mo3, etc
2. The Implementation Standard of 12Ni14 Steel Plate: EN10028-4(Hot Rolled Type), EN10222-2( Forged Type)
3. Delivery Status of 12Ni14 Steel Plate:
The steel plate is usually delivered by normalizing, [SCALE STEEL]normalizing and tempering, quenching and tempering
4. Chemical Composition of 12Ni14(%):
Mn: 0.30-0.80[SCALE STEEL]
5.Mechanical Property of 12Ni14 Alloy:
[GRADE] [DELIVERY STATUS] [THICKNESS
/MM] [YIELD STRENGTH
/MPa] [TENSILE STRENGTH/MPa] [ELONGATION/% MIN.]
/ EN10222-3 12Ni14] [N/N+T/Q+T] [≤30] [≥355] [490-640] 
6. Main Applications of 12Ni14 Alloy:
12Ni14 is one kind of nickel [SCALE STEEL]alloy materials for pressure equipment especially under low temperature, mainly used in building of pressure equipment, boiler, pressure vessel, LNG tanks, etc.
316Ti stainless steel plate is named 0Cr18Ni12Mo2Ti in international standard, and Chinese brand name is 1Cr18Ni12Mo2Ti stainless [SCALE STEEL]steel plate, 316Ti stainless steel plate is added Ti element in SUS316 to improve the resistance to intergranular corrosion. 316Ti stainless steel is used for equipment to resist sulfuric acid, phosphoric acid, acetic acid and acetic acid.
Physical Properties of 316Ti Stainless Steel:
C: 0.08 or less
Si 1.00 or less
Mn 2.00 or less
P 0.035 or less
S 0.030 or less
Ni 10.00 ~ 14.00 [SCALE STEEL]
Cr 16.00 ~ 19.00
Mo 1.80 ~ 2.50
Ti acuity 0.2 ~ 0.70
GB/T1220-1992 has this provision, usually also called Mo2Ti or 316Ti
YS (Mpa) ≥205
TS (Mpa) ≥520
EL (%) ≥40
Hv around 200 °
Thickness: cold-tied 2B plate (0.09 -- 6.0mm);
Hot rolled industrial plate No.1(3-50mm) [SCALE STEEL]medium thick plate, chemical plate, high temperature plate;
Width: 5mm-- 850mm steel belt;
1000, 1219, 1250, 1500, 1800, 2000mm coil plate, plate
Surface: 2B smooth surface, No.1 industrial surface, BA (6K) mirror, 8K mirror, 9K mirror, drawing surface, frosted surface.
Origin: Domestic, imported (Sweden,[SCALE STEEL] Japan, Finland, South Korea, South Africa, Taiwan)
Key Properties of 316Ti Stainless:
These attributes refer to products in similar, but not identical, attributes that are specified in other products, such as plates and forgings in their respective specifications. The lower minimum pre - and post-heat[SCALE STEEL] temperatures reduce the incidence of weld cracking and simplify welding. Low hardness decreases the heat affected zone to minimize deterioration in mold performance.
Introduction for 15NiMn6 Alloy Steel Plate:
1.15NiMn6 Is a nickel alloy steel plate for [SCALE STEEL]pressure applications. Standard: EN10028-4(Hot Rolled Type) or EN10222-3（Forged Type）.
2.15NiMn6 Dimensions, Shape, Weight and Allowable Deviation
The size, shape and allowable deviation of[SCALE STEEL] the steel plate shall meet the requirements of 2007+ A1:2009 in EN10028-1.
3.15NiMn6 Delivery Status
3.1 15NiMn6 Steel Plates are normally delivered in normalizing, normalizing and tempering condition.
3.2 Steel plates shall be delivered by [SCALE STEEL]shearing or flame cutting
4. Chemical Composition of 15NiMn6
The chemical composition of nimN6 steel (melting analysis) shall meet the following requirements (%) :
Chemical Composition Required for 15NiMN6 (%):
C 0.18 or less; Si 0.35 or less; [SCALE STEEL]Mn: 0.8-1.5; P 0.025 or less; S 0.015 or less; Al:-; Ni: 1.30-1.70; V 0.05 or less.
Elements not listed in this table shall not be intentionally added to steel without the consent of the demander, except after smelting, and all appropriate measures shall be taken during the steelmaking process to prevent the addition of [SCALE STEEL]these elements from scrap and other materials which may adversely affect the mechanical properties and serviceability of the steel. Among them: Cr + Cu + Mo 0.5 or less
5.1 15NiMn6 Mechanical Performance:
The mechanical and process properties of [SCALE STEEL]NIMN6 shall comply with the following table:
15NiMn6 mechanical requirements (transverse)
Grade Thickness Yield strength (MPa) Tensile strength (MPa) Elongation A(%)
15NiMn6 ≤30 ≥355 490-640 ≥22
15NiMn6 30-50 ≥345 490-640 ≥22
15NiMn6 50-80 ≥335 490-640 ≥22
The Relevant Family Steel Grades of P355NH:
P275NH, P275NL1, P275NL2, P355N, P355NH, P355NL1, [SCALE STEEL]P355NL2, P460NH, P460NL1, P460NL2.
Steel Grade Levels:
Room Temperature Quality Class: P355N
High Temperature Quality Grade: P355NH
Low Temperature Quality Grade: P355NL1, P460NL1
Special Low Temperature Quality Grade: [SCALE STEEL]P355NL2, P460NL2
P355N, P355NH, P355NL1, P355NL2 thickness 8-260mm
Tensile strength RM630-450mpa, yield strength: 355-295mpa, elongation after fracture 21-22%
Evaluation of Hydrogen Induced Crack Resistance
The evaluation test for hydrogen cracking resistance of steel plate products shall be carried out according to EN10229, and A test solution[SCALE STEEL] (PH 3) or B test solution (PH 5) and corresponding acceptance criteria can be selected.
HIC Test Acceptance Grade:
Acceptance grade: Grade I, Grade II, grade III
CLR% crack length ratio, CTR% crack [SCALE STEEL]thickness ratio, CSR% crack sensitivity ratio.
P355NH is used in Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, [SCALE STEEL]Luxembourg, Malta, The Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland, the United Kingdom.
S355NL Steel Plate belongs to standard of EN10025-3. Full Name: Normalizing/Normalizing rolled weldable fine grain structure steel plates. This standard together with EN10025-1 replaces EN 10113-1:1993 hot rolled steel products with weldable [SCALE STEEL]fine grain structure -- Part 1: General Conditions and EN 10113-2: Hot-rolled weldable fine grain structural steel products - Part 2: Conditions for normalizing/normalizing rolled steel. When the temperature is not less than -20°C, the minimum impact energy is specified, denoted by N. When the temperature is not less than -50°C, the minimum impact energy is specified, denoted by NL.
Name of Steels:
S: for structural steel, N: state, capital L: [SCALE STEEL]specifies the level of minimum impact energy at a temperature not lower than -50°C.
Strength: Tensile strength: RM630-450mpa. Yield strength: 355-275mpa, elongation after fracture 21-22%.
National Standards Corresponding [SCALE STEEL]to S355NL:
ASTM: Type 3 Grade 50
The Typical Application of S355NL Steel Plate:
Construction machinery, mining [SCALE STEEL]machinery, metallurgy, environmental protection, water conservancy and hydropower structural parts.
1. Carbon (C) : the yield point and tensile strength of steel increase with the increase of carbon content, but the plasticity and impact are reduced, when the carbon content is over
When the welding performance of steel is over 0.23%, [SCALE STEEL]the carbon content of low alloy structural steel used for welding is generally not more than 0.20%.
High carbon content will reduce the atmospheric corrosion resistance of steel, in the open yard of high carbon steel is easy to rust; In addition, carbon can increase Cold brittleness and aging sensitivity of steel.
2. Silicon (Si) : in the process of steel making, [SCALE STEEL]add silicon as a reducing agent and deoxidizer, so the killed steel contains 0.15-0.30% silicon.
If the silicon content in the steel exceeds 0.50-0.60%, silicon is considered an alloying element. Silicon can significantly improve the elastic limit, yield point and Tensile strength, so widely used as spring steel. Adding 1.0-1.2% silicon to quenched and tempered structural steel can increase the [SCALE STEEL]strength by 15-20%.
The combination of silicon and molybdenum, tungsten, chromium, etc., has the effect of improving corrosion resistance and oxidation resistance, and can make heat-resistant steel. Low silicon content of 1-4% Carbon steel, with high permeability, used for making silicon steel sheet in electrical industry. The increase of silicon will reduce the welding performance of steel.
3. Manganese (Mn) : in the process of steel making, manganese is a good deoxidizer and desulfurizer, general steel contains [SCALE STEEL]manganese 0.30-0.50%. in When carbon steel is added more than 0.70%, even if "manganese steel", more than the general amount of steel not only has enough toughness, and has a higher
Strength and hardness, improve the quenchability of steel, improve the hot working performance of steel, such as 16Mn steel is 40% higher than A3 yield point. 11%-14% manganese steel with extremely high wear resistance, used for excavator bucket, [SCALE STEEL]ball mill liner, etc. The increase of manganese content weakens the corrosion resistance of steel and reduces the welding performance.
4. Phosphorus (P) : in general, phosphorus is a harmful element in steel, increase the cold brittleness of steel, so that the welding performance deteriorates, reduce Plastic, so that the cold bending performance deteriorates. Therefore, phosphorus content in steel is usually less than 0.045%, and high quality steel is required to be lower.
5. Sulfur (S) : Sulfur is also a harmful element in general. Make steel produce hot brittleness, reduce the ductility and toughness of steel, in Cracks are caused by forging and rolling. Sulfur is also detrimental to welding performance, reducing corrosion resistance. So sulfur content is usually less than 0.055%, high quality steel requirements [SCALE STEEL]less than 0.040%. Adding 0.08-0.20% sulfur to steel can improve machinability Often called free cutting steel.
6. Chromium (Cr) : in structural and tool steels, chromium can significantly improve strength, hardness and wear resistance, but at the same time reduce plasticity and Toughness. Chromium also improves the oxidation resistance and corrosion resistance of steel, so it is an important alloying element in stainless steel and heat-resistant steel.
7. Nickel (Ni) : nickel can improve the strength of steel, while maintaining good plasticity and toughness. Nickel has high corrosion resistance[SCALE STEEL] to acid and base Strength, rust resistance and heat resistance at high temperature. However, as nickel is a scarce resource, other alloying elements should be used as far as possible Nickel chrome steel.
8. Molybdenum (Mo) : Molybdenum can refine the grain of steel, improve hardenability and thermal strength performance, and maintain sufficient strength and resistance at high temperature Creep ability (long-term under high temperature stress, deformation, called creep). The mechanical properties of structural steel can[SCALE STEEL] be improved by adding molybdenum. It can also inhibit the brittleness of alloy steel due to fire. Redness can be improved in tool steel.
9. Titanium (Ti) : titanium is a strong deoxidizer of steel. It can make the inner structure of steel compact, refine grain force; Reduced age sensitivity And cold brittleness. Improve welding performance. Intergranular corrosion of [SCALE STEEL]cr 18 ni 9 austenitic stainless steel can be avoided by adding appropriate ti.
10. Vanadium (V) : vanadium is an excellent deoxidizer of steel. Adding 0.5% vanadium to steel can refine grain structure and improve strength and toughness. vanadium
The carbides formed with carbon can improve the resistance to hydrogen corrosion at high temperature and pressure.
11. Tungsten (W) : tungsten melting point is high, significant, is expensive alloy elements. Tungsten forms tungsten carbide with carbon[SCALE STEEL] and has high hardness and resistance Grinding. The addition of tungsten to tool steel can significantly improve the red hardness and thermal strength, used as cutting tools and forging dies.
12. Niobium (Nb) : Niobium can refine grain and reduce steel overheating sensitivity and temper brittleness, improve strength, but the plasticity and toughness The decline. Adding niobium to ordinary low alloy steel can improve the corrosion resistance of atmospheric and high temperature hydrogen, nitrogen and ammonia. [SCALE STEEL]Niobium can Improve welding performance. Intergranular corrosion can be prevented by adding niobium into austenitic stainless steel.
13. Cobalt (Co) : Cobalt is a rare precious metal, mostly used in special steels and alloys, such as hot steel and magnetic materials.
14. Copper (Cu) : Wisco with daye ore smelting steel, often contain copper. Copper improves strength and toughness, especially for atmospheric[SCALE STEEL] corrosion The corrosion performance. The disadvantage is that it is easy to produce hot brittleness during hot working, and the plastic content of copper exceeds 0.5% is significantly reduced. When copper content is less than 0.50% has no effect on weldability.
15. Aluminum (Al) : aluminum is commonly used in steel deoxidizer. Adding a small amount of aluminum to steel can refine grain size and improve impact toughness, such as 08Al steel for deep drawing sheet. Aluminum also has oxidation resistance and corrosion resistance, aluminum combined with chromium, silicon, can significantly improve steel High temperature performance and high temperature corrosion resistance. The shortcoming of aluminum is affecting the hot working property, welding property and cutting property of steel Machining performance.
16. Boron (B) : adding trace boron to steel can improve the density and hot rolling properties of steel, improve the strength.
17. Nitrogen (N): nitrogen can improve the strength of steel, low temperature toughness and weldability, increase the aging sensitivity. Formation of bubbles and porosity.
18. Rare Earth (Xt) : Rare earth elements refer to the 15 lanthanide elements in the periodic table with atomic numbers from 57 to 71. Actually these elements are metals, but their oxides are so earth-like that they are commonly called rare earths. Adding rare earths to steel can change the steel- The composition, morphology, distribution and properties of inclusions improve various properties of steel, such as toughness, weldability, cold workability can add rare earth into ploughshare steel can improve wear resistance.