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seamless steel 440 is a kind of economic section steel. it is widely used in the manufacture of structural parts. Otai company provides it for our clients.

Seamless steel tube is a round, square, rectangular steel with a hollow section and no joints around it. A seamless steel tube is made of the ingot or solid tube blank through the perforation into a capillary tube, and then by hot rolling, cold rolling, or cold drawing. Otai company provides Seamless steel 440 for our clients.

Seamless steel pipe has a hollow section, a large number of pipe used for conveying fluid, steel pipe and round steel and other solid steel, in the same bending and torsional strength, weight is lighter, is an economic section of steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drilling steel scaffolding.

Use and classification of seamless steel tube

Application: A seamless steel tube is a kind of economic section steel, which has a very important position in the national economy. It is widely used in petroleum, chemical industry, boiler, power station, ship, machinery manufacturing, automobile, aviation, aerospace, energy, geology, construction, and military industry.

Classification:

(1)According to the section shape: circular section tube, shaped section tube

(2)According to the material: carbon steel pipe, alloy steel pipe, stainless steel pipe, composite pipe

(3)According to the connection: threaded connection pipe, welding pipe

(4) according to the production mode: hot rolling (extrusion, top, expansion) tube, cold rolling (drawing) tube

(5) according to the use of the following: boiler pipe, oil well pipe, pipeline pipe, structure pipe, fertilizer pipe

Seamless steel tube production process

(1) main production process of hot rolled seamless steel pipe (main inspection process) :

Preparation and inspection of tube billet → tube billet heating → perforation → rolling pipe → reheating of raw pipe → fixing (reducing) diameter → heat treatment → straightening of finished pipe → finishing → inspection (nondestructive, physical and chemical, table inspection) → storage

(2) cold rolling (drawing) seamless steel pipe main production process

Blank preparation → pickling lubrication → cold rolling (drawing) → heat treatment → straightening → finishing → inspection

If you want to know more about stainless steel 440, welcome to contact me.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

34CrNiMo6 Intorcution –Properties/chemical/application/heat treatment

34CrNiMo6 steel Intorcution –Properties/chemical/application/heat treatment

34CrNiMo6 is equal to 1.6582 .

The chemical of the grade for 34CrNiMo6 and 1.6582 as the below sheet :

The application of 34CrNiMo6:

34CrNiMo6 is a typical difficult-to-machine material, widely used in the manufacture of important parts such as camshafts and connecting rods of engines.

The 34CrNiMo6 alloy is high-strength. Because of its excellent comprehensive mechanical properties, it is widely used in the manufacture of engine camshafts and connecting rods and other important parts.

The stock for the specification as the below :

Mechanical properties of 34CrNiMo6 as the below mention :

After 34CrNiMo6 material is quenched and tempered, the hardness is 36-40 HRC, the tensile strength σb is 1 100 MPa, the elongation δ is 12%, and the impact toughness value ακ is 8 kg / cm2.

Heat treatment:

The tempering process of 34CrNiMo6 is 850 oil quenching and 580 degree tempering.

Quenched and Tempered (Q+T) of 34CrNiMo6 Steel

• Heat 34CrNiMo6 round steel slowly to the temperature of 850°C;
• Soak at this hardening temperature quench in oil;
• Temper as soon as 34CrNiMo6 steels reach room temperature.
• Heat uniformly to the suitable temperature;
• Withdraw from the furnace and cool in the air.
• The usual tempering temperature is 600°C which depending on the actual requirements.

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On one hand, the pandemic causes badly damage to the global economy, on the other hand, it takes a new chance for the special steel industry.

The pandemic takes the new chance for the special steel industry

On one hand, the pandemic causes badly damage to the global economy.on the other hand, it takes a new chance for the special steel industry. As a member of the Otai special steel company, we have faith we can finally fight the pandemic. We will take advantage of the chance to provide better steel for our customers. In 2020, we will insist on providing high-quality 4140 steel,p20 steel, and 440 Steel.

High-quality development currently requires the industrial chain to move from the low end to the high end. Because of this, the epidemic provides the special steel industry with an industry consolidation to achieve the survival of the fittest opportunity.

Due to the epidemic situation, the market demand for special steel products is insufficient. However, the production of special steel enterprises is not reduced during the epidemic period. The combination of the two factors leads to the sudden rise of inventory pressure. It also stimulates the prominent contradiction between market supply and demand. At the same time, the global epidemic makes it more difficult to export. Enterprises suffer multiple impacts. In general, the outbreak has a huge impact on the special steel industry, special steel demand, especially high-end special steel demand decline.

The future development trend of special steel

The future development trend of the special steel pandemic, we provide the different sizes of mask mold for the mask manufacture. If you want to know more about it, please contact me. must be that the demand for steel quality, performance, and variety is greater than the demand for steel quantity. In other words, it is the quality, performance, and variety of special steel that will lead and guide the future market.

To satisfy the requirement of the customer’s different sizes, we bought the new cutting machine. Otai devotes to improve the high-quality after sell service and better special steel for our customers .during the pandemic, we provide the different sizes of mask mold for the mask manufacture. If you want to know more about it, please contact me.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

The so-called non-quenched steel is a new kind of steel made by adding trace alloy elements such as V, Nb and Ti into medium carbon steel.In most cases the total amount of microalloys added is generally not more than 0.25% (0.25%).

Non-quenched steel’s advantages

The world’s first non-quenched steel was introduced in 1970 by GERLACH, a German company, which produced crankshafts using CK45 steel instead of the quenched steel they had just developed.Because the use of non-tempered steel production forgings can save the tempering treatment (quenching + high temperature tempering) in the process of two heating and energy consumption, so it has the advantages of energy saving and environmental protection, known as green steel.

Cost of heat treatment

In 1973, the Middle East war broke out, the high oil price forced people.they pay more attention to energy conservation and consumption reduction. Under this background, the development and utilization of non-quenched steel.it’s set off a climax in the west.with each country successively introducing its own non-quenched steel.By 1984, from non-quenched steel,60% of Japan’s crankshafts, 50% of its connecting rods were forged.The germans say, using 49MnVS3 non-quenched steel.It can instead of quenched steel.Aichi.A Japanese company, says that using non-quenched steel can cut costs by 18%.

Strengthening mechanism

Forgings, whether made of tempered steel or non-tempered steel.It cannot be used without strengthening treatment after forging.Different steels have different strengthening mechanisms.The strengthening mechanism of quenched steel is: First through quenching.The steel is made into martensite, and then the martensite is made into tempered sostenite by tempering treatment.

Tempered sostenite is a stable structure with good comprehensive mechanical properties.

Rather than the reinforcement mechanism of quenched and tempered steel. first, in the heating process,non quenched and tempered steel V, Nb, Ti.Alloy elements in the form of alloy carbon compounds, before forging fully dissolve in the austenite. and then,in the process of cooling after forging.The carbon and nitrogen compounds from austenitic alloy precipitation.Forming numerous small, scattered alloy carbon compounds.At the same time, the fine ferrite steel can improve the strength and hardness of steel.

Ms Sharon Wan

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Tel: 0086-769-23190193

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The development of non-quenched steel has gone through three stages.

The development of non-quenched steel has gone through three stages. The first generation of non-quenched steel is ferrite.Pearlite type non-quenched steel.The second generation is bainian type non-quenched steel.the third generation is low carbon martensionic type non-quenched steel.

Ferrite – pearlescent non – tempered steel.

At present, the largest amount of non – tempered steel, about 60% of the total amount.Compared with tempered steel, it has more strength than toughnes.So it is necessary to improve the toughness under the condition of guaranteeing the strength.

Development of non-quenched steel-Nippon steel

The Nippon steel researchers found,by properly controlling the production process.the austenite crystals were allowed to form a large number of ferrite nucleating cores.Then ferrite is formed not only in grain boundary, but also in austenitic crystal package.

These fine, evenly distributed ferrites make the steel remarkably more ductile.

Bayesian type non-tempered steel

It is a kind of strength and toughness is very good non quenched and tempered steel.In order to make the air cooling after forging can get bainite organization, after joined the molybdenum, manganese, boron in steel and other alloy elements.

The effect of manganese

When the content of it to a certain extent can make austenitic isothermal transformation curve is in the shape of epsilon to separate the steel C curve up and down;Boron can significantly delay ferrite transformation.

The combination of molybdenum of development of non-quenched steel

To boron or manganese – boron results in the bainite structure of steel over a wide cooling range.At the same time, manganese can reduce the phase change temperature.improve the toughness and enhance the strength.

Elements such as vanadium and chromium,they are usually added to low carbon bainitic steel,For makeing up for the decrease in strength caused,by the decrease in carbon content.

Martensioned non tempered steel

(1)

In 1988, an American steel company,first proposed the concept.third-generation non-tempered steel with low carbon tempered martensitic structure.

Similar to bainitic non-quenched steel, low carbon martensitic non-quenched steel has high toughness,as well as high strength.It has already been used in automobile walking parts and construction machinery.

(2)

At the same time, after the development and application of ferrite – pearlite (f-p), bainite (B), martensitic (M) non-quenched steel, ferrite – bainitic (F- B), ferrite – martensitic (F- M), composite phase non-quenched steel is gradually developed,and used because of low cost and excellent performance.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

The mechanical properties of non-quenched steel depend on the microstructure of matrix and the strengthening of precipitated phase.

Non quenched and tempered steel introduction

High strength steel used in rolling or normalizing state.

Its microstructure is mainly ferrite and pearlite. The method to improve the strength of non-quenched steel is to refine the structure by adding alloying elements and rolling. Silicon and manganese, which have little effect on weldability and are cheap, are often used as the main alloying elements in non-quenched steel. Controlled rolling can also refine the microstructure and improve the strength and toughness of non-quenched steel.

The typical steel types of non-quenched steel

(1) For ordinary welding structures, which are used in much the same way as mild steel, including Bridges, gas tanks, high-pressure vessels, building components, lifting machinery and civil machinery, etc.;(2) high-strength steel for shipbuilding;(3) high strength steel for gas pipelines.

Non-quenched steel are added vanadium, titanium and niobium microalloying elements

It makes it dissolve in austenite during heating because the solid solubility of vanadium, titanium, and niobium in austenite decreases with cooling. The microalloying elements vanadium, titanium, and niobium will be separated from the ferrite and pearlite in the form of nitride of fine carbides. These precipitates maintain a coherent relationship with the parent phase, strengthening the steel.The mechanical properties of this kind of steel in hot rolling, forging or normalizing state not only shorten the production cycle, but also save energy.

Non-quenched steel can be divided into non-quenched steel for hot forging

Non-quenched steel can be divided into non-quenched steel for hot forging, it’s for direct cutting, and for cold working and high toughness quenched steel. Non-quenched steel used for hot forging (such as crankshaft, connecting rod, etc.), non-quenched steel used for direct cutting is directly processed into parts with hot-rolled parts, cold-working non-quenched steel is used for standard parts (such as nuts, etc.), and high-toughness non-quenched steel is used for parts requiring higher toughness.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

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Chromium-nickel-molybdenum steel: represents steel type 4340/34CRNIMO6.It has excellent comprehensive mechanical properties.

4340/34CrNiMo6

Chromium-nickel-molybdenum steel: represents steel type4340/34CrNiMo6.It has excellent comprehensive mechanical properties, high impact toughness at low temperature, low notch sensitivity and no tempering brittleness.Used for making large crankshaft, shaft, connecting rod, gear, bolt and other parts with large force and complex shape.

More application of tempering steel

(1)

Cr,ni, mo, v steel: 45CrNiMoVA for steel type.High strength, good tempering stability, oil quenching up to 60mm (95% martensite).It is used to manufacture elastic shaft and torsion shaft of heavy truck under vibration load.

(2)

Chromium silicon steel: on behalf of the steel type 38CrSi.Hardenability is better than 40Cr, the strength and low temperature impact are higher, the tempering stability is better, the tempering brittleness tendency is greater.It is commonly used to manufacture 30-40mm shafts, bolts and gears with small modulus.

(3)

Chromium molybdenum steel: on behalf of steel 30CrMoA, 4140, ML30CrMo, ML42CrMo.Water quenching 30-55mm, oil quenching 15-40mm;High mechanical properties at room temperature, high strength at high temperature and good impact at low temperature;No tempering brittleness.Used for making parts with large section, bolts and gears with high load and flanges and bolts under 500℃;Conduit and fastener under 400℃.4140 has higher hardenability than 30CrMoA and is used for making parts with higher strength and larger cross sections.

(4)

Chromium manganese molybdenum steel: on behalf of the steel 40CrMnMo.The diameter of oil quenching is 80mm, with high comprehensive mechanical properties and good tempering stability.Used for manufacturing heavy load gear and shaft parts with large section.

(5)

Manganese molybdenum vanadium steel: on behalf of the steel 30Mn2MoWA.Good hardenability: water quenching up to 150mm, the heart structure is upper and lower bainite plus a small amount of martensite;Oil quenching 70mm, more than 95% martensite in the heart;Good low temperature impact toughness, low notch sensitivity and high fatigue strength.It is used to manufacture important parts under 80mm.

(6)

Chromium manganese silicon steel: on behalf of the steel 30CrMnSiA.Water quenching 40-60mm (95% martensite), oil quenching 25-40mm.High strength, impact toughness, temper brittleness.Used for manufacturing high pressure blower blade, valve plate, clutch friction plate, shaft and gear.

(7)

chrome-nickel steel: on behalf of the steel 40CrNi and 45CrNi.Water quenching up to 40mm, oil quenching up to 15-25mm;Good comprehensive mechanical properties, good low temperature impact toughness, little tempering brittleness.30CrNi3A has high hardenability, good comprehensive mechanical properties, white point sensitivity and temper brittleness.Used for making large section of crankshaft, connecting rod, gear, shaft and bolt.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

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Email: Sharon@otaisteel.com

1.2083 AISI 420 plastic mold steel is German DIN standard grade 1.2083, American AISI standard grade is 420.

1.2083 AISI 420 mold steel is suitable for electric corrosion operation, suitable for acid plastics and molds that require good polishing. It is mainly used in the production of PVC molds, wear resistance and filling molds. It is including thermosetting plastic molds, long-life molds. Such as: disposable tableware molds, optical product parts production, like cameras and sunglasses, medical containers, etc. .

Now this plastic mold steel 1.2083 AISI 420 is very hot popular in China because it is widely and hugely applied on the different mold tools. And the mold tools will be used on the different medical machines.
The epidemic is spreading rapidly around the world, which has a huge negative impact on global public health security. The global crisis seemed to bring the world into the long night. There is no borders on the virus.

Facing the epidemic situation, it is imperative for all countries to strengthen cooperation. Governments of various countries need to learn some experience. Like take strict detection and tracking measures, actively share knowledge about epidemic prevention and control. And establish temporary hospitals, allocate resources to the places where they are most needed through monitoring. Developed countries should consider providing assistance to developing countries and countries with weak public health systems when possible. The international community should work together to reduce the infection rate so that the medical system can effectively respond to the outbreak. Then make vaccines to be developed, and allow patients to receive timely and appropriate treatment.

Each piece of dark cloud is inlaid with gold. Despite the negative impact of the epidemic, we still have to see positive results. Over the past few years, global conferences have continually called on countries around the world. That is to work together to meet the challenges posed by climate change. But some countries are not attentive. After the outbreak of the New Coronary Pneumonia, many countries have adopted “closing the city” measures. It gives us the opportunity to think more deeply about the impact of humans on the planet and take effective measures in time to protect the common homeland of humanity.

Now it is the time for mankind to work together to create a common vision. This vision will promote people’s mutual concern and arouse people’s concern for the entire planet. If human beings expect to have a bright future, they must work together. When fighting against the epidemic, even if it falls into the long night. As long as the light of the community of human destiny shines, we can fill the world with warmth and love through solidarity and cooperation.
Otai undertakes every order to the end and solve customer’s problem without any hesitate on responsibility. That is why OTAI is professional in the special steel line for more than 21years.

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34CrNiMo6 Intorcution –classification and chemical analysis

34CrNiMo6 Introduction –classification and chemical analysis

classification:

① quenched and tempered structural steel

②Surface hardened structural steel

① The carbon content of quenched and tempered steels is generally about 0.25% to 0.55%. For structural parts of a given cross-sectional size, when quenching and tempering along the cross-section during quenching and tempering (quenching and tempering), the mechanical properties are good. If it is not quenched and free ferrite appears in the microstructure, the toughness decreases. For steels with a tendency to temper brittleness, such as manganese steel, chromium steel, nickel-chromium steel, etc., they should be cooled quickly after tempering. The critical quenching diameter of this type of steel increases with the increase in grain size and alloying element content. For example, 40cr and 35simn steel is about 30-40mm, and 40crnimo and 30crni2mov steel is about 60-100mm, which is commonly used in manufacturing Structural parts such as shafts and connecting rods with large loads.

②Surface hardened structural steel is used to manufacture hard and wear-resistant surface parts and flexible parts, such as gears and shafts. In order to increase the toughness of the core of the part, the carbon content in the steel should be low, generally 0.12 to 0.25%, and there is also an appropriate amount of alloying elements to ensure proper hardenability. Nitrided steel also needs to add alloy elements (such as al, cr, mo, etc.) that are easy to form nitrides. Carburized or carbonitrided steel, after carburizing or carbonitriding at 850 ～ 950 ℃, quenched and used under low-temperature tempering (about 200 ℃). The nitrided steel is directly treated by nitriding (480 ～ 580 ℃), and it is no longer quenched and tempered.

34CrNiMo6 (1.6582) belongs to European standard high-strength alloy structural steel.

According to the carbon equivalent calculation formula recommended by the International Welding Society (IIW) Ceq = C + 1 / 6Mn + 1/5 (Cr + Mo + V) +1/15 (Ni + Cu) (%)

(1) When Ceq <0.40%;

(2) When Ceq = 0.40 ～ 0.60%, the hardening tendency of the steel gradually becomes obvious, and the weldability is acceptable. When welding, appropriate preheating before welding and slow cooling after welding should be adopted to control its welding line energy;

(3) When Ceq> 0.60%, the steel has a strong hard tendency and poor weldability. It is a steel type that is more difficult to weld, and a higher preheating temperature and strict process measures must be taken to select suitable welding. material. It is calculated that the carbon equivalent value of 35CrMo steel Ceq = 0.72%.

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Our OTAI stocks 1.7225 42CrMo4 steel plates and keeps daily inventory of 1000tons. We are the biggest stockiest in south of China.

As this item is our hot selling items, we exports this 1.7225 42CrMo4 to more than 35 countries from EU, Middle East and Asia. The steel materials meet DIN, ASTM, EN, JIS and so on in different international standards.

Now as the virus affect, the material for this 1.7225 42CrMo4 and the DC53 steel material became the internet hot selling material now. Because the 1.7225 42CrMo4 is for the mask mold tool apply on the normal mask manufacturing.And the DC53 is for the mold tool using on the N95 mask manufacturing.

What we learn from this virus? 

And recently, I saw some report and news about the blame games for this virus. Sometimes, as the human being, we should learn something from this virus lessons. Sometimes, we underreact and in other situations we overreact, and for a reason. Facing the coronavirus, China, Japan, EU and USA all struggles, although for different reasons. China worried about sounding a false alarm and causing panic in January. When they knew little at the very beginning, by the time of the Wuhan lockdown, there were only 570 documented cases and 17deaths. These numbers were alarming but not very illuminating. The Chinese chose to overreact, they closed off an entire province, the size of Portugal and Hungary put together. But a month of data should have made a huge difference.

In late Feb many countries chose to underreact, they had other things to worry about. The Japanese did not want to delay the Olympics. The Europeans doubted the necessity to change their way of life. And the Americans hated to shut down what is the biggest world economy. Should we blame them? Maybe. But is is always easy to judge with the benefit of hindsight. Foresight is totally another thing. You could be right and you could be wrong.

Donald Trump said : I am instructing my administration to halt funding of the World Health Organization . While a review is conducted to assess the World Health Organization’s role in severely mismanaging and covering up the spread of the coronavirus.Today, America blamed the WHO for doing too little too late. In 2009, the WHO was also blamed but for a different reason. It was criticized for overreacting. The swine flu that originated from a Mexico farm was declared as a pandemic. Because it looked like and acted like one. It turned out to kill only 0.01 percent of the infected, lower than a seasonal flu. And the world paid a huge sum of money and human resources to contain it. People blamed the WHO for overshooting. To be continued…

Ms Phoenix Li

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