Category Archives: Blog

Posted

March 10, 2020 at 3:50 am

H-21 hot work tool steel, otai will satisfy your demand.

Maybe you heard a lot about hot work tool steel.However, do you know about the h21? H-21 hot work tool steel is perhaps the most widely used of the Tungsten steels. it belongs to the high-quality high carbon alloy tool steel. The 9.5% tungsten content imparts good resistance to softening at service temperatures while still maintaining adequate toughness.

Recently, several clients from Italy ask me whether otai company can provide h21 steel for them, of course, the answer is positive. We sold the h21 steel. They want to import the h21 steel from our company, they build springs, shaped parts and precision metal parts of all types and shapes, in particular for applications in the automotive, motorcycle, household appliances, and industrial plant engineering fields. While h21 is suitable steel for them.

Unlike the higher tungsten grades, H-21 may be cooled by the continuous flow of water if the design of the die will permit. Oil Quenched & Tempered Hardness is 28-34 HRc. AISI H21 steel Annealing delivery hardness less than 250HB.

Chemical Composition

Carbon 0.35

Manganese 0.25

Silicon 0.35

Chromium 3.50

Tungsten 9.50

Vanadium 0.50

Main Application

H21 hot work tool steel is particularly useful for hot forging and blanking dies and punches for making nuts, bolts, and other similar small components. Dies, cores, inserts, pins, etc for the die casting of copper-base alloys are also prime applications for this steel. Other uses include forming dies, shear blades, hot extrusion dies, mandrels, punches, die, holders, ejector discs and extrusion lines.

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. If you are ready to buy tool steel or carbon steel, please choose otai company, you will not regret it.Maybe you heard a lot about hot work tool steel,h13 is widely used tool steel. However, do you know about the h21? H-21 is perhaps the most widely used of the Tungsten hot work steels, it belongs to the high-quality high carbon alloy tool steel. The 9.5% tungsten content imparts good resistance to softening at service temperatures while still maintaining adequate toughness.

Recently, several clients from Italy ask me whether otai company can provide h21 steel for them. of course, the answer is positive. We sold the h21 steel. They want to import the h21 steel from our company, they build springs, shaped parts and precision metal parts of all types and shapes, in particular for applications in the automotive, motorcycle, household appliances, and industrial plant engineering fields. While h21 is suitable steel for them.

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

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Posted

March 9, 2020 at 8:04 am

H13 STEEL APPLICATION IN LIFE-Chapter 13

After FSLW experiments for H13 steel , samples were taken for tensile-shear testing and for metallography. Tensile-shear test samples and supporting pieces were 16 mm wide. Details of gripping a sample for testing, which is commonly used for testing lap joints, have been explained [11]. Samples were tested at a constant crosshead displacement rate of 3 mm/min using a 50 kN Tinus Olsen tensile machine. The strength of a lap sample cannot be expressed using the normal load/area expression, as the stress distribution along the joint area is highly uneven. Instead, maximum load in a test divided by the sample width, F_m/w_s, is taken as joint strength. For microstructure observation using optical microscope and SEM, the welds were cross-sectioned, mounted and polished following the normal metallographic procedure.

Advanced Characterization Techniques for Nanostructures

Jiménez et al. recently investigated a plasma-assisted physical vapour deposition technique to grow (TiAl)N films on H13 tool steel¹⁴. This tool steel is commonly used as a forming dye material at temperatures up to 600°C. Above this temperature the surface oxidizes and spalls quickly. In order to enable this tool material to be used at higher temperatures, a protective surface coating is needed. Thermal treatment of the H13 tool steel with and without (TiAl)N coatings were investigated with an AFM used in non-contact mode. Uncoated substrates showed appreciable increase in surface roughness due to oxidation at temperatures above 600°C whereas coated samples retained similar surface profiles after temperature treatments up to 1000°C (see Figure 3.4). X-ray diffraction (XRD) measurements were used to confirm and correlate these topographical measurements with the surface reactions. Extensions of the AFM, force modulation microscopy (FMM) and phase detection microscopy (PDM) were also used to image the surface. In FMM mode the tip is scanned in contact with the sample while a displacement sinusoid of a few kilohertz is applied to the tip or sample. The applied amplitude signal is modulated according to the elastic properties of the sample. FMM can therefore be used to image hard and soft regions at the same time as topological information is recorded. PDM is used when the AFM is operated in intermittent contact mode. PDM refers to the monitoring of the phase lag between an applied signal driving cantilever oscillation and the cantilever oscillation output signal. Changes in the phase lag reflect changes in the mechanical properties of the sample surface.

Tanaka et al. investigated the effect of toner particle morphology on toner fluidity and adhesion strength using an AFM¹⁵. Particle fluidity and interactions are influenced by surface structure size and morphology as well as the particle size and morphology. A fractal dimension was used to quantify the particle surface shape, which was related to its flow properties, and particle adhesion forces, which were measured with an AFM. The fractal dimensions were directly scaled from the nanostructure on the toner particle surfaces. A toner particle of approximately 5.5 μm diameter was attached to the AFM tip (see Figure 3.5), which was then held close to compacted toner powder (with a pressure of 54.9 MPa). The force to move the tip/particle away from the surface was recorded. Toner particles were nanotextured to various degrees by mixing with fine SiO₂ particles (mean diameter of 20 nm) which adhered to the toner particles. As the fractal dimension increased, the shearing and adhesion force between particles was also seen to increase.

Matějka et al. examined the wear characteristics of SiC-reinforced iron-phenolic based brake disks using an AFM¹⁶. Abrasives, such as SiC, are added to brake disk composites in order to increase the friction coefficient and stabilize it at higher temperatures. At temperatures above 250°C an enhanced pull-out of SiC was noted from the AFM results. The AFM results also showed that these particles could help maintain the friction coefficient at higher temperature due to their abrasion of the disk surface. A potential drawback of quicker abrasion of the contact surface was also reported. An optimum of approximately 3.4% SiC addition was determined from this work.

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Posted

March 9, 2020 at 7:56 am

The brief of H13 steel

The brief of H13 STEEL

The brief of h13 steel

H13 is a hot work tool steel that has good resistance to thermal fatigue, erosion and wears, and is widely used for making molds and dies. The H13 powder used for laser consolidation contains 0.42% C, 5.04% Cr, 1.33% Mo, 1.06% V, and 0.88% Si. LC H13 samples were metallurgically sound and free of cracks or porosity. LC H13 tool steel showed a directionally solidified dendritic microstructure with layered features: very fine columnar dendrites (around 1–2 μm in dendritic arm spacing) aligned along the vertical direction (Fig. 16.4A). Cellular features were observed along the transverse cross-section.

The XRD results indicated that the LC H13 steel consisted of a majority of α (martensite) plus a trace amount of γ phase (Fig. 16.4C), which was very similar to the H13 powder used for the consolidation except for the reduced amount of γ phase. Further XRD analysis indicated that the carbides extracted from the LC H13 material were of MC, M₇C₃, and possible M₃C types.

the properties of h13 steel

The LC H13 tool steel showed excellent tensile properties (Table 16.2). The average yield and tensile strengths of the consolidated H13 along the vertical direction were about 1288 and 2064 MPa, respectively, while the elongation was about 6% and the elastic modulus was about 216 GPa. Along the horizontal direction, the LC H13 showed significantly higher yield strength (1564 MPa) than along the vertical direction. while the tensile strength, elastic modulus, and elongation of LC H13 were comparable for both directions.

It should be noted that the tensile properties of the LC H13 material had relatively small scatter. For example, along the vertical direction, the standard deviations of the yield strength and tensile strength were about 54 and 51 MPa, respectively, while the standard deviations of the elastic modulus and elongation were 4 GPa and 2.2%, respectively, which indicated that the laser consolidated H13 material at a reasonably good consistency.

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Posted

March 9, 2020 at 7:49 am

H13 STEEL APPLICATION IN LIFE-Chapter 9

Like all dies, however, H13 steel is regrettable that they are not really permanent. An aluminum casting weighing up to 1 kg might be produced tolerably well for up to 80 000 or 100 000 shots before the die will require to be refurbished as a result of heat checking (cracks due to thermal fatigue of the die surface that produce a network of unsightly raised fins on the cast surface of H13 Steel).

Magnesium alloy high-pressure die castings of H13 steel are much kinder to dies, giving perhaps five times or more life. This is partly the result for H13 steel the lower heat content of Mg alloys, and partly because of the low solubility of iron in liquid magnesium that reduces its action to dissolve the die surface. In contrast, liquid Al has a relatively high solubility of iron, resulting in a phenomenon known as ‘soldering’ of the casting to the die. This action is particularly destructive to dies. It is countered to some extent by the addition of high levels of iron to high-pressure die-casting alloys, thus pre-saturating the liquid metal with iron and so greatly reducing the tendency for the melt of H13 steel to dissolve the die.

Attempts have been made to cast of H13 steel molten stainless steels by high-pressure die casting. In this case of H13 steel the only die material of H13 steel capable of withstanding the rigors of this process was an alloy of molybdenum. Even these ‘moly’ dies suffered early degradation by thermal fatigue cracking, threatening the commercial viability of the process. So far as the author is aware, partially solid (inaccurately called ‘semi-solid’) stainless steels have not been extensively trialed. These cooler mixtures that have already given up practically half of their latent and specific heat during freezing would greatly benefit die life. The commercial viability of the somewhat more expensive mixture would remain a potential show-stopper of course for H13 steel .

Because of the very high pressures for H13 steel involved in HPDC internal cavities are usually limited to those formable by straight withdrawable steel cores. If the core cannot be withdrawn then the usual alternatives such as sand cores are totally unsuitable because they are penetrated by the liquid metal. One of the H13 steel is very few options to make undrawable cavities in HPDCs are salt cores described below.

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Posted

March 9, 2020 at 7:48 am

H13 application –chapter11

The lubrication and cooling of steel moldIn order for H13 steel to decrease the heat load of mould, people always will make H13 steel cooling directly in the interval of work. However, this steel of H13 will cause a bad impact on the mold. It should be cool slowly to avoid thermal stress and cracking during the process of H13 . Need to use the graphitic lubricant to make sure the H13 steel die work in the right way. Its power of H13 radiating is great. That will decrease the temperature of H13 mold at the time of work.

How to fix it for H13 steel mould ?

Analysis of chemical composition and quality of material

Raise the purity of H13 steel. Decrease the content of sulfur which is the most efficient way to increase the working life of H13 steel mold. The sulfur content is at the range of 0.005-0.008% of high-quality H13 steel.

According to the analysis of chemical composition and quality of material can get the result of if it is eligibility. That will help us to make the right decision on the technology of heat treatment and forging for H13 mould steel . Test Method: Sampled the H13 steel stuff to analyze its chemical composition and if it complies to the requirements. And take the sample at the steel center. Then grinding, polishing, etching with 4% nitric acid alcohol solution, examining the microstructure on an optical microscope, and assessing the grade of carbide segregation and the grade of inclusion according to relevant national technical standards.

The way of technology control for H13 steel

Forging Technology The ingot that diameter bigger than 70mm must preheat at the temperature range of 800-900℃. Then, it is heated at an initial forging temperature of 1065 to 1175 ° C. And the total forging ratio must bigger than 4.
Spheroidizing Annealing It can make the strength get lower and improve the cutting machining properties. Do a good start for quenching and tempering. The spheroidizing annealing process is maintained at 845℃ to 900℃(1 h +1 min)/mm. And then cooled to 720℃ ~ 740℃ isothermal (2h + 1 min)/mm at the furnace. Cooling to 500 ° C at the furnace, and finally out of the furnace to air-cooled.
Quenching and Tempering Technology There is the best way of H13 steel heat treatment technology. After heating at 1020°C~1080°C, then oil hardening or martempering. Tempered twice at 560-600 °C. The microstructure is tempered toughness + tempered sorbite + residual carbide, and the microhardness is 48-52HRC.

The manufacture of H13 steel die must do a good job at design, the material chosen, forging, annealing, heat treatment and etc to make sure the quality at a high level. Every step is important and has a big influence on the mold product.

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Sharon

Posted

March 9, 2020 at 7:46 am

H13 steel manufacturing technique

H13 steel manufacturing technique-Forging Technology;Cutting;Grinding;electric spark;Heat treatment technology

Huge stacks of H13 tool steel in Dongguan China

H13 steel manufacturing technique effect the used of steel

Today,I collated some data from the internet,about the which processing will effect the used of steel.

(1) Forging process

H13 steel contains a lot of alloying elements, has a large resistance to deformation during forging, and has poor thermal conductivity of the material. The eutectic temperature is low, and it will overheat if you pay little attention. Therefore, when heating, it should be preheated in the range of 800 ～ 900 ℃, and then heated to the starting forging temperature of 1065 ～ 1175 ℃. In order to crush large non-metallic inclusions, eliminate carbide segregation, refine carbides, and even structure, repeat upsetting and upsetting during forging, and the total forging ratio is greater than 4. During the cooling process after forging, there is a tendency that quench cracks occur, and lateral cracks are liable to occur in the core. Therefore, H13 steel should be slowly cooled after forging.

(2) Cutting

The surface roughness of the cutting process has a great impact on the thermal fatigue performance of the mold. The mold cavity surface should have a low surface roughness without leaving knife marks, scratches and burrs. These defects cause stress concentration and induce thermal fatigue crack initiation. Therefore, during the processing of the mold, the corner radius of the complex part must be prevented from leaving knife marks, and the burrs on the edges of the holes, grooves and roots must be polished away.

(3) Grinding

During the grinding process, local frictional heat easily causes defects such as burns and cracks, and generates residual tensile stress on the grinding surface, which leads to premature failure of the mold. Burning caused by grinding heat can temper the surface of the H13 mold until tempered martensite is formed. The brittle untempered martensite layer will greatly reduce the thermal fatigue performance of the mold. If the grinding surface is locally heated above 800 ° C and the cooling is insufficient, the surface material will be re-austenitized and quenched into martensite, so the surface layer of the mold will generate high structural stress, and the grinding process The extremely rapid temperature rise of the middle mold surface will cause thermal stress, and the superposition of tissue stress and thermal stress will easily cause grinding cracks in the mold.

Next Chapter,I shall organize the rest,the other H13 steel manufacturing process.

Ms Sharon Wan

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Sharon

Posted

March 9, 2020 at 7:45 am

H13 die steel complete data

H13 (4Cr5MoSiV1) is a hot-working die steel widely used in the world. It has high thermal strength and hardness

H13 Tool Steel in the Otai Steel Warehouse in Dongguan

H13 (4Cr5MoSiV1) is a hot-working die steel widely used in the world.

It seems I had wrote much about H13 die steel but my friends told me that it’s ramdon data,they want a complete data,so I serch alot,and organized it.

It has high thermal strength and hardness, high wear resistance and toughness, and good thermal fatigue resistance. Hot extrusion dies and die casting dies for aluminum, copper and their alloys. Hot work die steel is subject to large impact loads, strong friction, thermal stress caused by severe cold and heat cycles, and high temperature oxidation, and often failure modes such as chipping, collapse, wear, and cracking.

AISI H13 Chemical composition

C(％)	0.32～0.45	Si(％)	0.80～1.20	Mn(％)	0.20～0.50
P(％)	≤0.030	S(％)	≤0.030	Cr(％)	4.75～5.50
Mo(％)	1.10～1.75	V(％)	0.80～1.20

Its chemical composition characteristics:

① Medium carbon, with a mass fraction of 0.32 to 0.45%, to ensure high hardness, high toughness and high thermal fatigue resistance.

② Add more elements Cr, Mn, Si to improve hardenability. Mn can change the nature and shape of the oxides formed during solidification of the steel, avoid sulfur forming low melting point FeS on the grain boundaries, and exist as a certain plastic MnS, thereby eliminating the harmful effects of sulfur and improving the heat of H13 die steel Workability; Cr and Si can improve tempering stability.

③ Add elements Mo and V that cause secondary hardening. Mo and V can also prevent the second type of tempering brittleness and improve the tempering stability.

The failure problem of H13 steel mold is a very complicated technical problem, which can be analyzed from four aspects: material, design, manufacturing and use.

Chemical composition and metallurgical quality

H13 die steel is a type of hypereutectoid alloy steel. There are many defects in the structure such as non-metallic inclusions, carbide segregation, center porosity and white spots, which greatly reduce the strength, toughness and thermal fatigue resistance of mold steel. H13 steel is generally divided into ordinary H13 steel and high-quality H13 die steel according to quality. Due to the use of more advanced production technology, high-quality H13 steel has pure steel, uniform structure, slight segregation, and higher toughness and thermal fatigue properties. Ordinary H13 steel must be changed to forge to crush large non-metallic inclusions, eliminate carbide segregation, refine carbides, and homogenize the structure.

Mould Design

When designing the mold, the external dimensions of the module should be determined according to the material and geometric dimensions of the formed part to ensure the strength of the mold. In addition, excessively small fillet radii, wide and thin wall sections with wide and thin wall sections, and improper positions of holes and grooves can easily cause excessive stress concentration and initiation of cracks during mold heat treatment and use. Therefore, avoid sharp corners as much as possible in the design of the mold, and the holes and slots should be arranged reasonably.

Ms Sharon Wan

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Tel: 0086-769-23190193

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Jack Otai

Posted

March 9, 2020 at 7:11 am

What’s the difference between sup6 and sup9?

Today, I receive an email from a client about sup6 steel. What’s the sup6 steel, what’s the difference between sup6 and sup9?

Although 4140 is the main product of the otai company, however, the sup9 is available if you need it. I will tell you the details about it.

Sup6 and sup9 both belong to the spring steel, spring steel is widely used in our daily life. even ballpoint pens we use are equipped with springs. It is also used in much mechanical equipment.

Features and Scope of sup6

sup6 Is widely used silicon manganese spring steel, strength, flexibility, and hardenability than 55Si2Mn. Suitable for railway vehicles, bear a greater load on the automobile and tractor industries flat spring or coil spring 30mm or less in diameter, and is also suitable for the production of working temperature below 250 ℃ non-corrosive medium heat and withstand alternating load spring and under high stress the important work of the large spring roll. High silicon content (Wsi) (up to 2.00%). High strength and good elasticity. Good resistance to tempering. Easy to decarburize and graphitize. Hardenability is not high. Manufacture of various springs, such as leaf springs, coil springs for automobiles, locomotives, tractors, cylinder safety valve springs.

Chemical Composition:

Carbon C: 0.56 ~ 0.64

Si Si: 1.50 ~ 2.00

Mn Mn: 0.60 ~ 0.90

Sulfur S: ≤0.035

Phosphorus P: ≤0.035

Chromium Cr: ≤0.35

Ni Ni: ≤0.35

Copper Cu: ≤0.25

SUP9-Characteristics

Sup9 Steel is a high-quality cold work spring steel. It belongs to high carbon alloy spring steel. Oil quenched and tempered hardness is 28-34 HRC. Sup9 annealing delivery hardness less than 250HB.

The outstanding advantage is that it has good hardenability, and also has good hot workability, comprehensive mechanical properties, and decarburization resistance. Various important springs with large cross-sections, such as large leaf springs and coil springs for automobiles and locomotives.

Chemical Composition:

Carbon C: 0.52 ~ 0.6

Si Si: 0.15~ 0.35

Mn Mn: 0.65~ 0.95

Sulfur S: ≤0.035

Phosphorus P: ≤0.030

Chromium Cr: 0.65~ 0.95

Mr Jack Tan

Tel: 0086-769-23190193

Fax: 0086-769-88705839

Email: jack@otaisteel.com

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Sharon