The influence of 49 elements on the properties of steel!

Steel,as an important basic material in modern industrial society,has a direct impact on the performance of various applications in machinery,construction,transportation and other fields.The performance of steel is not static,but is affected by a variety of elements.Today,we will analyze in detail the effects of 49 elements on the performance of steel to help you better understand and choose steel materials.

1.Hydrogen(H)

Hydrogen is one of the most harmful elements in general steel.Hydrogen dissolved in steel can cause defects such as hydrogen embrittlement and white spots.At high temperatures,hydrogen dissolves into molten steel and does not have time to escape during cooling,so it accumulates in the structure to form high-pressure fine pores,which sharply reduce the plasticity,toughness and fatigue strength of the steel.In severe cases,it can cause cracks and brittle fractures.Hydrogen embrittlement mainly occurs in martensitic steels and is not very prominent in ferrite steels.In addition,hydrogen can increase the magnetic permeability of steel,but it will also increase coercivity and iron loss.

2.Boron(B)

The main role of boron in steel is to increase the hardenability of steel,thereby saving other rare and precious metals such as nickel,chromium,molybdenum,etc.For this purpose,its content is generally specified in the range of 0.001%to 0.005%.It can replace 1.6%nickel,0.3%chromium or 0.2%molybdenum.However,it should be noted that boron has a slight tendency to promote temper brittleness,so molybdenum cannot be completely replaced by boron.Adding boron to medium carbon steel can improve the performance of steel after quenching and tempering.For example,40B and 40MnB steel can be used to replace 40Cr,and 20Mn2TiB steel can be used to replace 20CrMnTi carburizing steel.However,the effect of boron weakens or even disappears as the carbon content in the steel increases.

3.Carbon(C)

Carbon is the main element after iron,which directly affects the strength,plasticity,toughness and welding performance of steel.When the carbon content in steel is below 0.8%,as the carbon content increases,the strength and hardness of the steel increase,while the plasticity and toughness decrease;but when the carbon content is above 1.0%,as the carbon content increases,the strength of the steel decreases.In addition,as the carbon content increases,the welding performance of the steel deteriorates,the cold brittleness and aging sensitivity increase,and the atmospheric corrosion resistance decreases.

4.Nitrogen(N)

The effect of nitrogen on steel properties is similar to that of carbon and phosphorus.As the nitrogen content increases,the strength of steel significantly increases,the plasticity,especially toughness,decreases significantly,the weldability becomes worse,and the cold brittleness intensifies.At the same time,nitrogen will also increase the aging tendency and damage the welding performance and cold bending performance of steel.Therefore,the nitrogen content in steel should be minimized and limited.Generally,the nitrogen content should not be higher than 0.018%.However,in combination with elements such as aluminum,niobium,and vanadium,nitrogen can reduce its adverse effects,improve the properties of steel,and is used as an alloy element in low-alloy steel.

5.Oxygen(O)

Oxygen is a harmful element in steel.It naturally enters the steel during the steelmaking process.Although manganese,silicon,iron and aluminum are added for deoxidation at the end of the steelmaking process,it is impossible to remove it.Oxygen mainly exists in the form of inclusions such as FeO,MnO,SiO2,and Al2O3 in steel,which reduces the strength and plasticity of the steel and has a serious impact on fatigue strength,impact toughness,etc.Oxygen will also increase the iron loss in silicon steel,weaken the magnetic permeability and magnetic induction intensity,and intensify the magnetic aging effect.

6.Magnesium(Mg)

Trace amounts of magnesium can improve the size and distribution of carbides in bearing steel.The carbide particles in magnesium-containing bearing steel are small and uniform.When the magnesium content is 0.002%to 0.003%,its tensile strength and yield strength increase by more than 5%,and the plasticity remains basically unchanged.

7.Aluminum(Al)

Aluminum is added to steel as a deoxidizer or alloying element,and its deoxidizing ability is much stronger than silicon and manganese.The main function of aluminum in steel is to refine grains and fix nitrogen in steel,thereby significantly improving the impact toughness of steel and reducing cold brittleness and aging tendencies.Aluminum can also improve the corrosion resistance of steel,especially when used in combination with molybdenum,copper,silicon,chromium and other elements.However,aluminum will affect the hot workability,welding performance and cutting performance of steel.

8.Silicon(Si)

Silicon is an important reducing agent and deoxidizer in the steelmaking process.Silicon can be dissolved in ferrite and austenite to improve the hardness and strength of steel.Its effect is second only to phosphorus and stronger than elements such as manganese,nickel,chromium,tungsten,molybdenum,and vanadium.However,when the silicon content exceeds 3%,the plasticity and toughness of steel will be significantly reduced.Silicon can improve the elastic limit,yield strength and yield ratio of steel,as well as fatigue strength and fatigue ratio,so silicon or silicon-manganese steel can be used as spring steel.Silicon can also reduce the density,thermal conductivity and electrical conductivity of steel,and improve the oxidation resistance of steel at high temperatures.

9.Phosphorus(P)

Phosphorus is brought into steel from ores,and is generally said to be a harmful element.Phosphorus can increase the strength and hardness of steel,but it causes a significant decrease in plasticity and impact toughness.Especially at low temperatures,it makes the steel significantly brittle,which is called"cold brittleness".Cold brittleness deteriorates the cold working and weldability of steel,so the phosphorus content in steel is strictly controlled.High-grade high-quality steel P<0.025%;high-quality steel P<0.04%;ordinary steel P<0.085%.However,phosphorus has good solid solution strengthening and cold work hardening effects.When used in combination with copper,it can improve the atmospheric corrosion resistance of low-alloy high-strength steel.

10.Sulfur(S)

Sulfur comes from steelmaking ore and fuel coke,and is a harmful element in steel.Sulfur exists in steel in the form of iron sulfide(FeS),and FeS and Fe form a low melting point(985°C)compound.The hot working temperature of steel is generally above 1150-1200°C,so when the steel is hot-worked,the workpiece will crack due to the premature melting of the FeS compound,which is called"hot brittleness".Sulfur will also reduce the ductility and toughness of steel,and is not good for welding performance and reduces corrosion resistance.However,sulfur chips are brittle and can produce a very shiny surface,which is used to make steel parts(such as free-cutting steel)that require low load and high surface finish.

11.Other Elements

Manganese(Mn):It can improve the strength of steel,weaken and eliminate the adverse effects of sulfur,and improve the hardenability of steel.High manganese steel has good wear resistance and physical properties.

Tungsten(W):can improve the red hardness and thermal strength of steel,and improve the wear resistance of steel.

Chromium(Cr):It can improve the hardenability and wear resistance of steel,and improve the corrosion resistance and oxidation resistance of steel.

Molybdenum(Mo):can improve the hardenability of steel and prevent or reduce temper brittleness.

Nickel(Ni):can increase the strength of steel,improve the low-temperature toughness of steel,and improve the corrosion resistance of steel.

Vanadium(V):can improve the strength and toughness of steel,refine grains,and improve the hardenability of steel.

Titanium(Ti):can improve the strength and hardness of steel,refine the grains,and improve the welding performance of steel.

Cobalt(Co):can increase the hardness and wear resistance of steel,and improve the steel's resistance to high temperature oxidation.

Copper(Cu):can improve the atmospheric corrosion resistance and high temperature oxidation resistance of steel.

Tin(Sn):It can improve the corrosion resistance of steel,but it will reduce the strength and hardness of steel.

Antimony(Sb):It can improve the hardness and wear resistance of steel,but it will reduce the toughness and plasticity of steel.

Bismuth(Bi):has little effect on the mechanical properties of steel,but can improve the corrosion resistance of steel.

Lead(Pb):It can improve the cutting performance of steel,but it will reduce the strength and hardness of steel.

Arsenic(As):It has little effect on the mechanical properties of steel,but can improve the corrosion resistance of steel.

Selenium(Se):It can improve the oxidation resistance of steel,but it will reduce the toughness and plasticity of steel.

Zirconium(Zr):can improve the strength and toughness of steel and improve the welding performance of steel.

Niobium(Nb):It can improve the strength and toughness of steel,refine the grains,and improve the hardenability of steel.

Tantalum(Ta):can increase the hardness and wear resistance of steel,and improve the steel's resistance to high temperature oxidation.

Hafnium(Hf):can increase the strength and toughness of steel and improve its corrosion resistance.

Ruthenium(Ru):It can improve the hardness and wear resistance of steel,but it is expensive and is generally not used in ordinary steel.

Rhodium(Rh):It can improve the hardness and wear resistance of steel,but it is expensive and generally not used in ordinary steel.

Palladium(Pd):It has little effect on the mechanical properties of steel,but can improve the corrosion resistance of steel.

Silver(Ag):It can improve the corrosion resistance of steel,but it is expensive and is generally not used in ordinary steel.

Cadmium(Cd):It can improve the cutting performance of steel,but it is toxic and is generally not used in ordinary steel.

Indium(In):It has little effect on the mechanical properties of steel,but can improve the corrosion resistance of steel.

Tin(Sn):It can improve the corrosion resistance of steel,but it will reduce the strength and hardness of steel.

Thallium(Tl):It has little effect on the mechanical properties of steel,but it is toxic and is generally not used in ordinary steel.

Barium(Ba):It can improve the corrosion resistance of steel,but it will reduce the strength and toughness of steel.

Lanthanum(La):can improve the strength and toughness of steel and improve the corrosion resistance of steel.

Cerium(Ce):Similar to lanthanum,cerium can also increase the strength and toughness of steel and help improve the corrosion resistance of steel.In some cases,cerium can also be used as a deoxidizer and desulfurizer.

Praseodymium(Pr):Praseodymium has little effect on the mechanical properties of steel,but can be used as one of the rare earth elements to help improve the microstructure and properties of steel.

Neodymium(Nd):Neodymium is also a rare earth element.It can improve the strength and toughness of steel and help refine the grain size of steel.

Promethium(Pm):Promethium is a radioactive element that is generally not used in steel production.

Samarium(Sm):Samarium can be used as a rare earth element additive to help improve the corrosion resistance and thermal strength of steel.

Europium(Eu):Europium is also a rare earth element.It has little effect on the mechanical properties of steel,but helps to improve the microstructure and properties of steel.

Gadolinium(Gd):Gadolinium can increase the strength and toughness of steel,and also helps improve the corrosion resistance of steel.

Terbium(Tb):Terbium has little effect on the mechanical properties of steel,but can be used as one of the rare earth elements to help improve the microstructure and properties of steel.

Dysprosium(Dy):Dysprosium can improve the strength and toughness of steel,and also help improve the steel's resistance to high-temperature oxidation.

Holmium(Ho):Holmium can be used as a rare earth element additive to help improve the strength and toughness of steel.

Erbium(Er):Erbium can improve the microstructure of steel and increase its strength and toughness.

Ytterbium(Tm):Ytterbium has little effect on the mechanical properties of steel,but can be used as one of the rare earth elements to help improve the corrosion resistance of steel.

Lutetium(Lu):Lutetium is also a rare earth element.It can increase the strength and toughness of steel and help improve the microstructure of steel.

Francium(Fr):Francium is a radioactive element that is generally not used in steel production.

Radium(Ra):Radium is also a radioactive element and has no practical application value in steel production.

Actinium(Ac):Actinium is a radioactive element that is generally not used in steel production.

Thorium(Th):Thorium can be used as a trace alloying element in steel,helping to improve certain properties of steel,but attention should be paid to its radioactivity.

Protactinium(Pa):Protactinium is a radioactive element that is generally not used in steel production.

Uranium(U):Uranium is also a radioactive element and has no practical application value in steel production.

Plutonium(Pu):Plutonium is a highly radioactive element and its use in steel production is strictly prohibited.

Summarize

The properties of steel are affected by a variety of elements,each with its own unique role.Understanding the impact of these elements on steel properties will help us better select and use steel materials.In steel production,we need to reasonably control the content of various elements according to specific application scenarios and performance requirements to obtain the best steel performance.

At the same time,we also need to note that some elements,such as radioactive elements,are strictly prohibited from being used in steel production to avoid harm to the human body and the environment.Although some rare elements such as tungsten,molybdenum,vanadium,etc.can significantly improve the performance of steel,they also need to be reasonably controlled during use due to their high price.

To sum up,the performance of steel is a complex and comprehensive issue,which requires us to comprehensively consider the influence of various elements and make selections and adjustments based on the actual situation.Only in this way can we obtain steel materials with excellent performance and meet the needs of various applications.