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42CrMo4 4140 material is an important steel type as a reducer structural part. For parts made of this steel, it is required to have comprehensive mechanical properties with good combination of strength and toughness. Because the equipment, materials and process technology operations are difficult to master at present. Some parts are prone to cracking during the tempering process. And these parts have obvious characteristics compared with other parts. Only by fully mastering these characteristics can we obtain satisfactory results. .

Generally speaking, the main factors affecting the quality of forging quenching and tempering include as following.

(1) Ingredient segregation. 42CrMo4 4140 steel is a medium carbon alloy structural steel, and its raw materials often have band-shaped segregation. From the analysis results of 42CrMo4 band component segregation energy spectrum, it can be seen that the Mo content in the ferrite band is 5-6 times higher than that in the pearlite band. The enrichment of some elements in the segregation stripes is very serious.
(2) Gas and inclusions. 42CrMo4 steel, especially the raw materials with large cross-section, inevitably contains gas and inclusions. For medium carbon alloy structural steel, due to the segregation of carbon and alloy elements, it may cause forgings Cracking occurs at the segregation. In addition, the presence of aluminum elements is also harmful to steel.

(3) Forging temperature. As this steel is segregated inside. When it is heated close to the solidus in an oxidizing atmosphere, if the high temperature duration is too long, it is easy to produce precipitates or impurities. Due to the low melting point, the grain boundary of the metal may start to melt. Oxygen invades through the melted grain boundary and forms oxides on the grain boundary. This will cause local over-firing and form one of the major defects in subsequent thermal processing.
(4) Forging ratio. When the forging ratio is insufficient, the deformation of the center of the workpiece is small. And the segregation and the original ingot structure of the steel ingot are still partially retained. If the forging ratio is too large, the anisotropy of mechanical properties increases, and the transverse mechanical properties decrease more.

Experimental research shows that due to problems of forging process and heat treatment process. 42CrMo4 4140 steel obtains mixed structure and complex stress distribution after quenching. And the workpiece is often cracked in batches or more. No matter what original state 42CrMo steel is sub-temperature quenched. The impact toughness after high temperature tempering is significantly better than conventional quenching and tempering. The controllable gas multi-purpose furnace is used for easy-cracking forgings for isothermal quenching, high temperature tempering and more stable.

Our Otai does not act as material handler. We have our own technique as we are on this steel field for more than 21years. We cut down the cost for distributor, and solve the different kinds of difficulties for the end users.

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

OTAI supplies 4140 special steel which is produced by the only one imported advanced steel making equipment.  buy 4140 steel and 1045 steel from us.

Our warehouse always keeps the daily stock for the 4140 steel plates in 1000Tons each day, so we are the largest stockist in south of China. After through the 21years steel business no matter in the domestic and overseas, we got the very good reputation from our customers. So they make the repeat order to buy 4140 steel and other steel grades from us very often. Some new customers may have some concerns on the quality when they placed the first buying. So it really is very important to find the reliable supplier with long history to buy 4140 steel.

Through about 3 months fighting with virus, now the situation was well controlled in China. And it is getting better and better. And what we learned from this virus? And what will the epidemic change?
The epidemic has brought us a perceptible impact, from politics to economy, from thought to life. In the 21st century, the coronavirus has not only created countless scenes that have never appeared in history, but it is almost reshaping human society.

Everything of Crisis moments also bring us opportunities to adopt a healthier and more inclusive attitude to life. More advanced and humane modern technology, and better governance method. After spending an uncertain period together, this virus will eventually force us more new change.
1. In a high-risk society, community governance will be more important.
2. Big cities will be stronger.
3. Public open space will become the core competitiveness of the city.
4. The pandemic prompted us to change social media.
5. From a single respect for scientists, to some questions.
6. Social distance narrows social relations.
7. The coronavirus epidemic will affect the structure of human nature to a certain extent.
8. The real estate demand side will undergo important changes.
9. The new learning center will appear like Taobao.
10. When the medical staff’s aura fades, the contradiction between doctors and patients will still come back.

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

Customer needs 4140 Shaft for Sugar Cane Machine

Today, there is a customer’s forged round steel of 4140, and it has to do Q + T and car light state. The required diameters are all 300mm or more. Then we asked the customer about the purpose of the product he inquired about. The customer said that the round steel he inquired about was used as the main shaft of the sugar cane machine. It happens that we have provided those kind of shafts to many foreign customers, especially customers in the Americas, who also use this large round steel as the mechanical spindle. We send the picture records to the new customers.

Property for 4140 Shaft

Customers are very interested in the products we supply. At the same time, we also asked customers about the mechanical performance requirements and technical standards he wanted. The customer sent the technical standard requirements in time, and our engineers carefully checked the customer’s standard requirements, and confirmed them one by one before replying to the customers. Because this is a processing product, compliance with technical requirements is the most important. We have raised our objection in one of the customer’s technical requirements. The customer requires that the diameter tolerance should be plus or minus 1mm, however the common diameter tolerance for turned round bar is controlled to be +/- 2mm to +/- 5mm. After the customer has heard our technical advice, the customer can also accept the conventional diameter tolerance that we can do. After the technical review is confirmed, the customer will ask us to make a quotation, and then do further review. But the client said that if it’s technically approved, it should be smoother later.

Important Things for those 4140 Shaft

• Usually, we supply turned surface with desired tolerance.
• The heat treatment is usually required as Q+T (quenching & tempering) or  N (normalized).
• Fixed length is required according to customer’s final use.

We are glad to offer you complete solution for those 4140 shaft for sugar cane machine requests. Contact us anytime.

Mr. Jeremy H.

Mobile/WhatsApp: 0086-13610149979

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jeremy@otaisteel.com

The price of 42crmo4 steel will decrease after labor day. It is a good choice for you to buy the 42crmo4 at Otai company.

The price of 42crmo4 steel will decrease after labor day. because of the pandemic, the demand for masks increased very fast. mask factory has to buy more mask mold to produce the masks. So they invest lots of money to buying the 42crmo4 and cr12mov, DC 53 steel to produce the mask mold. Especially in China, the population is huge, the masks are badly needed in the first three months of 2020.

Fortunately, it is easy to get the mask now, we can easily to get the masks, we can freely buy it at the nearby pharmacy shop. So supply is super demand, fewer people buy the mask mold .so the 42crmo4 supplier has a lot of storage. The price of it turns normal. If anyone wants to buy the 42crmo4, welcome to contact me, the price is really worthy.

The pandemic is still very serious outside of china, I hope the fight with the invisible disease will be end soon. As a mask mold supplier, Otai company supplies amount of material for the mask factory in china .we have faith we can supply the high-quality of mask mold material for the customers abroad. We provide the N95 mask mold made of 42crmo4, the common mask mold made of cr12mov, and DC 53 steel. We hope the pandemic will disappear like a miss, people’s life will turn to be normal.

AISI 4140 steel has high ductility. It can be formed using conventional techniques in the annealed condition. It requires more pressure or force for forming because it is tougher than plain carbon steel.

The types we can provide about 42crmo4

AISI 4140 All Steel, we can supply the round bar, steel flat bar, plate, hexagonal steel bar, and steel square block. steel Round bar can be sawn to your required lengths as one-offs or multiple cut pieces. 42CrMo4 alloy steel Rectangular pieces can be sawn from flat bar or plate to your specific sizes. Ground tool steel bar can be supplied, providing a quality precision finished bar to tight tolerances.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

Many friends asked for the steel code lately,then I collect some as below.

American standard AISI Steel Code:

P1 – P19: LowCarbon Steel

P20-p39: Low Carbon, High Alloy Steel(plastic die Steel)

2 xx, xx, xx 4, 6 xx: Stainless Steel (Stainless Steel)

H1-h19: Chromium base (Chromium base – hot working steel)

Wx: Water Hardening Steel

Sx: Shock Resisting Steel

Ox: OilHardening Steel (Steel)

Ax: AirHardening Steel

Dx: High Carbon, High Chromium Steel

Mx: Molybdenum base (H.S.S.- high speed steel)

German standard DIN Steel Code:

Low carbon, high alloy (p20-plastic die steel)

Lowcarbon, high alloy (p20-plastic die steel)

Lowcarbon, high alloy, free Machine (p20-free cutting)

StainlessSteel (420 – acid-fast steel)

1.2316: Highperformance stainless Steel (420 – high acid Steel)

1.2343: Chromiumbase (Chromiumbase -H11 – hot working steel)

1.2344: Chromiumbase (chromium-based -H13 – hot working steel)

Lowalloy steel (o1-oil steel)

1.2379: Highcarbon, high chromium steel (D2 — chromium steel)

Japanese standard JIS Steel Code:

SxxC: Plain Carbon steel(yellow card-s55c)

SUSxx: Stainless Steel, acid Steel – 420)

SCrx: Chromium Steel

SCMx: Chromium Molybdenum Steel (P20)

SKx: Carbon Tool Steel

SKSx: Low Alloy Steel (oil steel-o1)

SKD11: MediumHigh Alloy Steel(chromium-d2)

SKD6: Medium High Alloy Steel(Medium High Alloy Steel -H11)

SKD61: Medium High Alloy Steel(Medium High Alloy Steel –H13)

SKHxx: High Speed Steel (hs-m 2)

SUMx: Free Cutting Steel

SUJx: Bearing Steel

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

According to the life of the mold into five grades, the requirements of mold steel:

Generally, the mold is divided into five grades according to the length of service life.

Level NO1:more than a million times,

level NO2：is 500,000 to 1 million times,

level NO3:is 300,000 to 500,000 times,

level NO4: is 100,000 to 300,000 times, and level 5 is less than 100,000 times.

The first and second grade molds are required to use heat treatment

Hardness in HRC50 or so of steel, otherwise it is easy to wear, the injection of the product is prone to out of tolerance, so the selected steel should have good heat treatment performance, and in the state of high hardness has good cutting performance, of course, there are other considerations.

Usually choose Sweden’s die steel

(1)

8407, S136, the United States of mold steel 420, H13, Europe’s 2316, 2344, 083, or Japan’s SKD61, DC53 (the original metal mold material, special circumstances use).

(2)

Strong corrosive plastic generally choose S136, 2316, 420 and other steel, weak corrosive in addition to mold steel S136, 1.2316, 420, and JIS SKD61, NAK80, PAK90.

Product appearance requirements

(1)

It also have a great impact on the choice of mold materials, transparent parts and surface requirements mirror products, materials available are S136, 2316, NAK80, PAK90, 420, the transparency of the mold should be selected S136, followed by 420.

(2)

There are many pre-hard materials for the three-stage mold,mold steel grades are S136H, 2316H, 083H, and the hardness is HB270-340.

Mold steel

P20, OT718, 738, OT618, 2311, 2312, 2711 are used for grade 4 and grade 5 molds. For the molds with extremely low requirements, S50C and S45C steel may be used, which is to directly make a cavity on the mould blank.

If you want to know more or any suggestion,please conract me,let’s discuss more.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

As you know, Otai sells different kinds of round steels. however, do you know about it?

Round steels are a long bar of solid steel with a circular section. The specification is expressed in diameter in mm (mm)

Classification of round  steels

Round steel is divided into hot rolling, forging, and cold drawing. The specification of hot rolled round steel is 5.5-250mm. Among them: 5.5-25mm small round steel is mostly supplied in bundles of straight bars and is commonly used for reinforcing bars, bolts, and various mechanical parts; round steel with diameter  More than 25 mm, mainly used for making machine parts, seamless steel tube billet.

Commonly used material of round steel

Q195, Q235, 10#, 20#, 35#, 45#, Q215, Q235, Q345, 12Cr1Mov, 15CrMo, 304, 316, 20Cr, 40Cr, 20CrMo, 35CrMo, 42CrMo, 40CrNiMo, GCr15, 65Mn, 50Mn, 50Cr, 3Cr2W8V, 20CrMnTi, 5CrMnMo, etc.

standard of round steels

Standard: (gb699-1988, gb700-1988, gb3077-1988, gb702-1986, QJ/ hg02.17-1991)

The difference between round steel and other rebars:

1 appearance is not the same, round steel appearance light circle, no grain without rib, other rebar surface appearance has cut grain or have rib, so as to cause round steel and the concrete bonding force is small, and another rebar and the concrete bonding force are large.

2 composition is not the same, round steel (grade steel) is common low carbon steel, other steel reinforcement for alloy steel. Three different intensity, low intensity of round steel and other steel with high intensity, the diameter of the same size of round steel compared with other steel bars, round steels can withstand strength than other bar is small, but the plastic is better than other steel round steels, the round steels before is pulled with large deformation, and other steel before being pulled deformation is much smaller.

Theoretical weight

Theory of round steels weight calculation formula: outer diameter *diameter *0.00617 kg/m=weight of per meter

As for carbon steel, The carbon content is less than 1.35%, except for iron, carbon, and impurities such as silicon, manganese, phosphorus, and sulfur within the limit, steel without other alloying elements. The performance of carbon steel mainly depends on the carbon content. With the increase of carbon content, the strength and hardness of steel increase, and the plasticity, toughness, and weldability decrease. Compared with other steels, carbon steel is the earliest to be used, with low cost, wide performance range, and the largest consumption.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

There are three main ways to change the properties of die steel steel:Alloy composition、Smelting process、Heat treatment

There are three main ways to change the properties of die steel steel:

1、Alloy composition

Carbon: C

Increase the hardness of quenched tissue;

Forming carbide to improve wear resistance;

Reduced toughness;

Reduce weldability

Cr: Cr

Increase the hardness of steel, forming hard and stable chromium carbide, thus improving wear resistance;

Can improve the hardenability of steel;

When Cr content exceeds 12%, it is resistant to corrosion and provides good optical rotation

Mo, Mo

Mo is a strong carbide forming element to improve wear resistance.

Mo b b 0 0.5% can restrain the tempering brittleness caused by other alloy elements.

Provide red hardness, thermal intensity;

Increase the hardenability, temper stability

V: V

High hardness carbides can be formed to improve wear resistance.

Fine steel grain, reduce the sensitivity of overheating

Improve the strength, toughness and tempering stability of steel

Nickel: Ni

Ni can increase the hardenability of die steel;

Ni refines grains

Sulfur (S)

Often exists in steel in the form of MnS, breaks the continuity of matrix, deteriorates the material’s toughness, corrosion resistance, optical rotation, discharge processing, etch, can improve the cutting ability of the material.

2、Smelting process

Common steelmaking process

(1) electroslag remelting (ESR)

The thick billet is placed in the electroslag furnace, and a strong current is put into the furnace to produce a very high temperature, so that the thick billet is melted into molten steel, and the molten steel flows through the electroslag, and the impurities are filtered and absorbed by the electroslag, so as to achieve the purification effect.The overall remelting is fast, but some very fine impurities are not removed.

(2) vacuum arc remelting (VAR)

In a vacuum furnace, a strong electric current is applied to the steel shell. The bottom of the steel shell begins to melt, and the impurities are vaporized into gas and pumped away, thus improving the purity of the steel.It is characterized by thorough removal of impurities but slow overall remelting.

3、Heat treatment

The heat treatment of die steel refers to the process of heating and then cooling, by controlling the heating temperature, holding time and cooling speed of steel to change the properties of steel, in order to meet the requirements of processing or use.The main heat treatment processes are: annealing, quenching, tempering.

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

In the production process of iron and steel plate products, when the blank is pressed, the surface wrinkle, the surface is not flat phenomenon, is a common punching defect.

This not only leads to the waste of raw materials, sometimes also increases the subsequent scrap, such as automotive stamping parts wrinkle, will directly lead to the welding process after welding poor quality or even welding joint cracking.So how does the wrinkling happen?

When the steel plate is pressed and deformed, it is subjected to the tensile stress in the plane drawing direction and the compressive stress in the plate thickness direction.Under certain pressure, the thinner the plate, the easier to wrinkle.

At the same time, during the processing, the maximum tangential compressive stress appears on the edge of the flange, that is, the wrinkle on the outer edge is the most obvious.

Product wrinkling mainly from three aspects to find the reasons:

1、Parts design

Is the product model reasonably taking into account the molding problem, is the press bar set too small?Does the place that crinkle easily need to add to absorb crinkle rib?

Solution: increase the bar or change the layout of the bar.Add wrinkle absorbent to scrap section.

2、Process design

A) the pressure surface is loose and tight

Solution: repair the grinding press surface.

B) unreasonable shape of filling surface

Solution: modify the shape of the feed surface to avoid the uneven material flow caused by its shape immobility.

C) reasons for blanks.The blank is too small or the blank is not positioned properly in the mold

Solution: increase the blank size.Improve the blank positioning on the mold so that the mold can accurately press the steel plate.

D) too little pressure

Solution: increase the mandrel pressure.

E) the gap between upper and lower modules is too large

Solution: adjust the gap.

F) the fillet radius of the die mouth is too large, which makes the punch unable to press the material

Solution: reduce the radius of the fillet.

G) too much grease

Solution: apply oil according to the requirements of the operation regulations to ensure the correct position and amount of oil applied

3、Materials

The yield strength of the material is not up to the standard and the material is too soft.

Solution: to ensure the product performance, the use of better formability of materials.

For different cases, specific problems need to be analyzed, but in the final analysis, it is still inseparable from the above principles.With such a train of thought, if encounter corresponding problem again, you do not need to worry about this little wrinkle again!

Ms Sharon Wan

Mobile/WhatsApp: 0086-13580960968

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: Sharon@otaisteel.com

SCM440 Steel Plate Mold for Mask Machine direct use . The mold have machined , heat treated , for mask manufacture .

quivalent material

• ♦JAPAN♦ : JIS SCM440 alloy steel

• ♦GERMANY♦ : DIN WN-r 1.7255 / 42CrMo4 steel alloy

• ♦CHINA♦ :  GB 42CrMo steel

• ♦BRITISH♦ : BS 708M40

• American : AISI 4140

SCM440 Steel Plate Mold for mask machine provided by Otai Special Steel . Otai Special Steel promised that we reponsible for work for Anti-coronavirus . As coronavirus infected all over the world . And all Chinese are fight with them as people on the earth . We provide all kinds of steel materials use for mask machine . Such as : 4140 , 4Cr13 , Cr12MoV .

SCM440  alloy steel material is a high quality Quenched and Tempered Alloy Structural steel . It belong to the high quality medium carbon alloy steel, Oil Quenched & Tempered Hardenss is 28-34 HRC . 4140 Annealing delivery hardenss less than 250HB .

SCM440 Steel Plate Mold for Mask Machine finished direct use . Could exported to all over the world . If you have any demands . we can supply the round bar, steel flat bar, plate, hexagonal steel bar and square, block . 4140 alloy steel Round bar can be cut to your required lengths as one offs or multiple cut pieces . Rectangular pieces can be cut from flat bar or plate to your specific sizes. Ground tool steel bar can be supply, providing a quality precision finished bar to tight tolerances .

SCM440 Alloy steel material stockholders and suppliers from China-OTAI SPECIAL STEEL . we have more 16 years experience in SCM440 steel plate, round bar, flat bar, square supply . AISI 4140 alloy steel is chromium, molybdenum, manganese containing low alloy steel . It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength .

SCM440 Tool steel is a alloy structural steel, 4140 is used for engineering structural, like high tensile shafts, bolts and nuts, gears, pinions and spindles. Locomotive traction with the big gear, supercharger drive gear, pressure vessel, rear axle, gear load of connecting rod and a spring clip,4140 can also be used to under 2000 m deep well of oil drill pipe joint and the fishing tool, and can be used for bending machine mould, etc

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com