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Global Steel Industrial have effected by COVID-19 – Preview

The global crisis, a large number of steel mills shut down! 40% of domestic steel mills lost money, and European steel prices fell back to 2009

In January-February, China Steel Association’s steel companies have lost more than 40% of their losses

Now member steel companies are basically on the brink of loss

The spread of the epidemic has exceeded all expectations, and the situation facing the steel industry and the market is confusing.

Chi Jingdong, vice chairman of the China Iron and Steel Association, said: “No one expected that it would be as serious as it is now. The whole world has reached a situation that is a little bit out of control. The new and old problems of the Chinese steel industry are superimposed and under the impact of the epidemic, Where will it go again? ”

Two months ago, the Chinese steel companies at that time were in an awkward position: the raw materials were difficult to enter, the materials were difficult to come out, and the inventory was rising … A person in charge of a large state-owned steel company told the Economic Observer, “The first quarter It ’s good to lose money. ”

the expertise’s prediction about the steel market

However, Chi Jingdong introduced, “The loss of member steel companies in January-February has exceeded 40%. Now the profit margin of member steel companies has fallen to almost 1%, which is basically at the edge of loss.”

His prediction for the future steel market is: In the short term, April steel prices will fluctuate within a narrow range with high probability. It is not always possible that profits will drop sharply, but good benefits are also difficult. If the foreign market is not good after April and May, at least the steel price in the first half of the year will be unsatisfactory. If the epidemic is delayed until June or July, the impact will be greater.

Chi Jingdong believes that this year the steel industry and the market are at great risk, and it is recommended that steel enterprises should be prepared to deal with the market decline.

In this steel test, the difficulties, problems and even deep-seated contradictions of the entire industry and enterprises themselves were exposed.

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Email: Jack@otaisteel.com

Maybe we hear a lot about AISI 440 steel. Do you know that it can be divided into three types? It contains 440A,440B,and 440C.

Classification of AISI 440 steel

Maybe we hear a lot about AISI 440 steel. It contains 440A,440B,and 440C. 440C is commonly used as making a knife. Otai special steel company provides 440 steel for our clients.

440C stainless steel is modern steel, known among all stainless steel alloys for its high corrosion resistance, abrasion resistance. It has good strength and hardness qualities, after heat treatment up to HRC60 hardness.

Application of AISI 440 steel

This steel can be used to make cutting tools, rolling bearings, valve seats, high-quality cutting tools. It is also used as surgical instruments, chisels, ball bearings . cutting tools such as barber blades, surgical blades, daggers, and blades are also made with 440 steel.

The grade of 440C is exactly the same as that of 440A and 440B.But it has a slightly higher carbon content. Although these three kinds of steel are the same grade of standard steel, in fact, 440C is more practical than A and B.

The 440C was the undisputed king of blade steel around the 1980s, a position that was not replaced by ats-34 until the 1990s. Even a novice blade maker can make a good blade with 440C if he can handle heat treatment and surface treatment well. And when well maintained, the blade of this material is excellent and durable.

Please note that 440A and 440B are alloy steels very similar to 440C and are often confused.But they are not suitable for the blade. The 440C is probably more suitable than any other alloy stainless steel for the cutting tool industry .and it is capable of a wide range of sizes and USES.

And now 440 steel families, there is a new type of modern steel known as 440V. Basically, this is an improvement of 440C steel. The steel has a similar hardness to the 440C. but it has greater corrosion resistance and machining capability.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

Application of tempering steel

Medium carbon tempering steel:

on behalf of the steel C30.C35.C40.C45.It also have ML30.ML35.ML40. ML45. A more stable room temperature performance, used for small and medium-sized structural parts, fasteners, transmission shaft, gear, etc.

Manganese steel

on behalf of the steel 40Mn2, 50Mn2.Have superheat sensitivity, high temperature tempering brittleness. water quenching easy to crack. hardenability is higher than carbon steel.

Silicon manganese steel

On behalf of the steel 35SiMn, 42SiMn.High fatigue strength. decarburization、 overheating sensitivity&temper brittleness.It is used to manufacture gear, shaft, rotary shaft. connecting rod and worm with medium speed and high load but little impact. It can also manufacture fasteners under 400℃.

Boron steel

On behalf of steel 40B. 45B. 50BA. ML35B.Hardenability is high, comprehensive mechanical properties are higher than carbon steel, and 40Cr is suitable for the manufacture of small section size of parts, fasteners, etc.

Manganese boron steel

On behalf of the steel 40MnB.Hardenability slightly higher than 40Cr. high strength, toughness and low temperature impact toughness, temper brittleness.40MnB is often used to replace 40Cr,it make large-section parts and 40CrNi to make small parts.45MnB replaces 40Cr and 45Cr.45Mn2B replaces 45Cr ,parts of 40CrNi and 45CrNi as important shafts, and ML35 MnB is also used for fastener production.

Manganese vanadium boron steel

On behalf of the steel 20 MnVB, 40MnVB.

Tempering performance and hardenability is better than 40Cr.overheating tendency is small, there is temper brittleness.It is often used to replace 40Cr.45Cr.38CrSi. 42CrMo4 and 40CrNi in the manufacture of important tempering parts.

Manganese tungsten boron steel

On behalf of the steel 40MnWB.Good low temperature impact performance, no tempering brittleness.Similar to 35CrMo and 40CrNi, it is used to manufacture parts under 70mm.

Silicon, manganese, molybdenum and tungsten steel:

on behalf of the steel type 35SiMn2MoW.

It has high hardenability. Calculated by 50% martensite, the water quenching diameter is 180, and the oil quenching diameter is 100.The tendency of quenching cracking ,and the tempering brittleness are small.High strength and high toughness.It can replace 35CrNiMoA, 4340, used to manufacture large section, heavy load shaft, connecting rod and bolt.

Silicon manganese molybdenum tungsten vanadium steel

On behalf of the steel type 37SiMn2MoWVA.Water quenching diameter 100, oil quenching diameter 70.Good tempering stability, low temperature impact toughness, high temperature strength, low tempering brittleness, used for manufacturing large section of shaft parts.

Chrome steel

Represented by 40Cr and ML40Cr.Good hardenability, water quenching 28-60mm, oil quenching 15-40mm.High comprehensive mechanical properties, good low temperature impact toughness, low notch sensitivity, temper brittleness.Used for manufacturing shaft, connecting rod, gear and bolt.

To be continued

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

The hardness of tempered parts

At the same time, the hardness after quenching and tempering,for the parts,it can reflect the yield strength and tensile strength, so the parts drawings and technical conditions generally,it only specify the hardness value.Only very important parts are subject to other mechanical properties.

The determination of the hardness

The determination of the hardness,the tempered parts must take into account,the requirements of the manufacturing process,and the load conditions during use.From the perspective of manufacturing process,in the blank state ,it is hoped that the parts can be tempered,and then machined and assembled.In this way, the deformation and decarburization during heat treatment,they are eliminated in later cutting.

Requirements

Requirements of higher hardness of the parts:such as some automotive half shaft,which hardness requirements is 341 ~ 415HB,it can only be cut, and then conditioning treatment, when the parts heating should prevent decarburization and deformation, sometimes,after heat treatment to increase the alignment process.For small batch or single piece parts, the hardness allowed by machining can be increased appropriately.

Characteristics of production

When determining the hardness,tempered parts must also consider the characteristics of production, small batch of single production of products, different parts can be selected different hardness, mass production of factories hope,that most parts of the hardness range is consistent,in a few hardness range, which is very convenient for the organization of heat treatment production.

The view of the use of parts

To determine the hardness of the tempered parts to pay attention to the working conditions, and the shape of parts.Generally speaking, high hardness value, tensile strength, yield strength and fatigue strength of the smooth sample is high, but the plasticity index, brittle failure tendency,and the sensitivity of the stress concentration increases.

Therefore, when the parts has stress,the concentration effect of gap (spline, groove, or change of section), in order to make uniform stress distribution, reduce the stress concentration phenomenon, then the lower hardness can obtain higher fatigue performance instead.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

Alloy tempered steel is widely used in the manufacture of various important parts of automobiles

Alloy tempered steel

Alloy tempered steel is widely used in the manufacture of various important parts of automobiles, tractors, machine tools and other machines, such as gears, axles, connecting rods, bolts and so on.Most of the tempering and tempering parts bear a variety of working loads, the stress situation is relatively complex, the requirements of high comprehensive mechanical properties, that is, with high strength and good plasticity.

(1) medium carbon: the carbon mass fraction is generally between 0.25% and 0.50%, with a majority of 0.4%;

(2) add the elements Cr, Mn, Ni, Si to improve the hardenability: these alloy elements can not only improve the hardenability, but also form the alloy ferrite, improve the strength of steel.For example, the performance of 40Cr steel after tempering is much higher than that of 45 steel.

(3) add elements to prevent the second type of tempering brittleness: alloy tempered steel containing Ni, Cr and Mn, the second type of tempering brittleness is easy to occur when tempering at high temperature and cooling slowly.Adding Mo and W to steel can prevent the second type of tempering brittleness, and its appropriate content: the mass fraction of Mo is 0.15% ~ 0.30%, or the mass fraction of W is 0.8% ~ 1.2%.

At present, the most widely used alloy tempered steel is 4140,4340,8620, their basic information is as follows

Heat Treatment of SAE 4140 Alloy tempered steel

• ASTM 4140 Steel Annealing

Slowly heat to 800～8500 ºC, keep enough time, ensure heat thoroughly. then cooling in furnace to 480 ºC, then cool in air. After annealing, the hardness 92 HBS Max.

• AISI 4140 Steel Hardening & Quenching

4140 Steel is usually used at 18-22 HRc, If needs, AISI 4140 alloy steel can be hardened or Quenching by cold work. Quenching medium: oil

• Tempering Of ASTM 4140 Alloy tempered steel

/ ℃ tempering temperature: 205 ~ 649°C.

After tempering hardness HRC: 18-25 HRC.

Heat Treatment of SAE 8620 Alloy Steel

• Annealing of 8620 Alloy tempered steel

Slowly heated to 850 ℃ and allow enough times, let the steel to be thoroughly heated, Then cool slowly in the furnace. The 8620 alloy steel will get MAX 250 HB （Brinell hardness）.

• Hardening of 8620 Alloy structural steel

Heated slowly to 880-920°C, Then after adequate soaking at this temperature quench in oil. Temper as soon as tools reach room temperature.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

C45 quenched and tempered steel

C45 quenched and tempered steel

C45 steel is carbon structure steel, hot and cold processing performance is good, mechanical performance is better, and low price, wide source, so it is widely used.Its biggest weakness is the hardenability is low, large cross section size and high requirements of the workpiece is not suitable.

C45 steel quenching temperature in A3+(30~50) ℃

It is generally taken upper limit.The high quenching temperature can accelerate the heating speed, reduce the surface oxidation, and improve the efficiency.In order to make the austenite of the workpiece uniform, it needs enough time for insulation.If the actual furnace load is large, it is necessary to appropriately extend the insulation time.

Otherwise, the phenomenon of insufficient hardness may occur due to uneven heating.However, if the insulation time is too long, the grain size will also appear, serious defects of oxidation and decarburization, affecting the quenching quality.

heating and holding time should be extended by 1/5.

Because C45 steel hardenability is low, so should use cooling rate of large 10% brine solution.After the workpiece enters the water, it should be quenched thoroughly, but not cold. If the workpiece cools thoroughly in the brine, it may cause the workpiece to crack. This is because when the workpiece cools to about 180℃, the austenite rapidly changes to martensite, resulting in excessive tissue stress.Therefore.

When the quenching workpiece quickly cold to the temperature of the region, should take a slow cooling method.Because the water outlet temperature is difficult to grasp, must operate by experience, when the shaking of the workpiece in the water stops, the water outlet air cooling (such as oil cooling is better).In addition, the workpiece into the water should not be static. It should be in accordance with the geometric shape of the workpiece, regular movement.Static cooling medium plus stationary workpiece, resulting in uneven hardness, uneven stress and workpiece deformation, even cracking.

Hardness of C45 steel quenched

Hardness of C45 steel quenched parts should reach hrc56-59, and the section may be lower, but not lower than HRC48, otherwise, it means that: the workpiece has not been completely quenched, sostenite and even ferrite may appear in the tissue, which is still retained in the matrix through tempering, so as to reach the purpose of tempering.The tempering temperature of 45 steel after quenching is usually 560~600℃, and the hardness is HRC22~34.

Because the purpose of tempering is to obtain comprehensive mechanical properties, the hardness range is relatively wide.But the drawing has the hardness request, must adjust the tempering temperature according to the drawing request, in order to ensure the hardness.If some shaft parts require high strength, high hardness requirements;And some gear, with keyway shaft parts, because after conditioning, but also milling, insert processing, hardness requirements are lower.

About tempering insulation timeaccording to the hardness requirements and the size of the workpiece, we believe that the hardness after tempering depends on the tempering temperature, and the tempering time is not relevant, but must be back through, generally the tempering insulation time of the workpiece is always more than an hour.

The commonly used alloy tempered steels are divided into 4 categories according to hardenability and strength:

(1) quenched steel with low hardenability;

(2) quenched tempered steel;

to be continued

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

Tempered steel, generally refers to the carbon content in 0.3-0.6% of medium carbon steel.

1 introduction

The so-called tempered steel, generally refers to the carbon content in 0.3-0.6% of medium carbon steel.Generally, the parts made of this kind of steel are required to have good comprehensive mechanical properties, that is, to maintain a high strength and have good plasticity and toughness, people often use tempering treatment to achieve this purpose, so people used to call this kind of steel tempering steel.Tempered steel is widely used in the structural parts of all kinds of machines.

Quenched martensite in the temperature range of 500~650℃.After tempering, the strength, plasticity and toughness of the steel have a good match.The composition of tempered steel is carbon 0.25% ~ 0.5% carbon steel or low alloy steel and medium alloy steel.Tempered steel is widely used in the structural parts of all kinds of machines.The most widely used quenched steels are chromium quenched steels (such as 40Cr, 40CrSi), chrome-manganese quenched steels (such as 40CrMn), chrome-nickel quenched steels, (such as 40CrNiMo, 37CrNi3A), boron-containing quenched steels, etc.

2 performance characteristics

In addition to the general metallurgical low and high power structure requirements.the main mechanical properties of steel,and the cold brittle transition temperature.fracture toughness and fatigue resistance, which are closely related to the reliability.Under specific conditions, it is also required to have wear resistance, corrosion resistance and certain heat resistance.Due to the use of high temperature tempering,the stress in the steel can be completely eliminated, the hydrogen embrittlement failure tendency of steel is small, the notch sensitivity is low, the brittle failure resistance is large.

Most tempered steel are of medium carbon alloy construction with yield strength (0.2) of 49-1200 mpa.It is a low carbon alloy structural steel with a yield strength (0.2) of 490-800mpa and high plasticity and toughness.A few precipitated hardened tempered steels with yield strength (0.2) up to more than 1400Mpa belong to high strength and ultra high strength steel.

to be continued.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

DC 53 steel is a good chioce for the mask mold manufacture .If you can’t choose a suitable material, the mold may be fractured.

(4) Advantages in surface hardening treatment

The surface hardness after surface hardening is higher than that of SKD11, so the mold performance can be improved.

(5) Advantages in repairing welding operations

Since the preheating and post-heating temperatures are lower than SKD11, the repair welding operation is relatively simple.

One of our clients bought the cheaper steel to make the mask mold to save the money. The mold fractured in a short period .so he loses much as the machines don’t work. so we should choose the good steel material to produce a good product. Compared with other materials,the DC53 steel is much better .it is durable.

There are some points we need to remind to fulfill the DC 53 steel application.

In the forging process of DC53 steel die material, it is necessary to control the initial forging temperature and the final forging temperature. The initial forging temperature is controlled at 1000-1200℃ and the final forging temperature is controlled at 850-900℃. After forging, it is necessary to use asbestos or dry sand for heat preservation and slow cooling, or immediately enter the box furnace with atmosphere control for annealing treatment, the annealing temperature is 830-850℃, according to the effective thickness of the mold to determine the heat preservation time, and then the furnace cold to 550℃ below before air cooling.

Otai Steel offers both technical advice and support, as well as global professional steel solution and service. Due to satisfactory reliable quality and professional service, Otai expands our market worldwide, such as UAE, Canada, Brazil, Colombia, Chile, Spain, Turkey, Algeria, Vietnam, Malaysia and so on. Welcome to consult .

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

DC 53 steel is a good chioce for the mask mold manufacture, If you can’t choose a suitable material, the mold may be fractured.

Recently, many clients bought DC 53 steel from our company. I would like to write an article about it. with the breakout of the corona-19, we need many masks to prevent the pandemic .so the mask makers have to buy more mask mold to produce the masks.

However ,which material is better for the mask manufacture? SKD11 maybe a good choice . DC 53 steel is much better if you choose this one. If you can’t choose a suitable material, the mold may be fractured.

Why many mask factory in china choose the DC 53 steel from our company? Our company not only provides the high-quality steel product but also the skills consultation.

In the process of mold design and manufacturing, the R Angle radius should be kept above 0.50mm in such parts as sharp Angle, groove and step, to avoid the risk of mold heat treatment and cracking during use due to stress concentration.

APPLICATION OF DC53 STEEL

1. Punching mold, cold forming mold, cold drawing mold
2. Forming rolls, punches

Precision stamping die

Precision blanking die for wire cutting and stamping die for various purposes

Tool for plastic deformation of difficult-to-machine materials

Cold forging, deep drawing, and boring die

other

High-speed punching punch, stainless steel plate punch

DC53  steel Practical features:

(1) Machinability and good abrasiveness.

The machinability and the abrasiveness are superior to those of the SKD11, so the processing tool has a long life and the number of processing hours is relatively low.

(2) Advantages of heat treatment

Quench hardening is higher than SKD11, so it can improve the defects of insufficient hardness during vacuum heat treatment.

(3) Advantages of online cutting processing

High-temperature tempering can reduce the residual stress and eliminate the residual Worthfield iron, which can prevent the cracking and deformation of the wire cutting process.

To be continued

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

1.2311 Mould Steel Materials could use for N95 Mask machine production . Dongguan Otai Special Steel could provide to export all over the world .

1.2311 Mould Steel Materials is a mould materials for plastic injection . it belong to the high quality medium carbon,Pre-hardness(28~34HRc) .  Cold work plastic mould steel. It no need further heat treatment. so you don’t have any worry about distortion or cracking. 2311 steel is most widely used to plastic mold material in injection plastic mould.

DIN 1.2311 tool steel, we can supply the round bar, flat bar, plate, hexagonal and square block . Diameters can be sawn to your required lengths as one offs or multiple cut pieces . Rectangular pieces can be sawn from flat bar or plate to your specific sizes . Ground tool steel bar and precision ground steel plate can be supplied, providing a quality precision finished bar to tight tolerances .

1.2311 Tool steel is a German Die steel, the steel by “super clean” production process, pre hardened, showing the height of micro pure and excellent homogeneous structure, excellent polishing and light etching engraving. After heat treatment, processing and polishing performance is good, can be carried out, and can be processed, suitable for the surface treatment of chrome, material hardness even (to 400mm thick), good toughness, good mechanical processing performance. Gold microstructure is martensite and bainite structure.

Main be applied to in zinc, aluminum, magnesium and its alloy die-casting mould ; Hot-pressing mold, all kinds of hot forging die; Metal extrusion die, die set.

So this time , we could use them for N95 mask mould  . 1.2311 Mould Steel Materials could best match with mask manufacture .

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com