Basic knowledge of the hottest die steel

2022-08-13
  • Detail

Basic knowledge of die steel

I. Basic Classification

1 There are many kinds of steel, among which the steel for mold is divided into three categories:

A. plastic mold steel: high gloss

B. hot working tool steel: high strength and high temperature resistance

C. cold working tool steel: high pressure resistance and wear resistance mdash; mdash; lsquo; High speed tool steel rsquo; It is a branch

2 Common brand marks:

smdash; mdash; Japanese industrial specification

tmmdash; mdash; ASTM specification

simdash; mdash; American Iron and Steel Association specification

nmdash; mdash; German national specifications

II. Usage practices

1 P20, the most commonly used plastic steel

s5, is similar to P20, but harder to process than P20. The disadvantage is that the temperature is higher and it is easy to harden

s1, which is not equal to S45C. It is not used in the cavity. It is used in the mold base to reduce the cost

4 If durability is required, the mold base material S50C or S55C, the common domestic solution is S45C forging, which has higher hardness and better wear resistance than S50C note: someone once said that S45C forging is better than S50C wear resistance. In fact, this S50C may be suspected of fake and inferior products

5 When the hardness of cavity steel is higher than P20, NAK80 can be selected, which is conducive to durability

6 Selection tendency:

a. plastic steel: that is, it is used in plastic injection molding, and then distinguish the requirements of mirror polishing and corrosion resistance

b. cold working steel: it is used in standard parts of guide post sleeve, as well as precision hardware mold or wear-resistant plastic mold or cold stamping mold

c. hot working steel: aluminum or zinc alloy die-casting mold

7 Many plastic steels are pre hardened to avoid heat treatment deformation

8 Composition tendency of various steels: medium carbon: C content 0.3mdash; 0.8%

A. plastic steel: medium carbon or low carbon, a small amount of nickel chromium system (1mdash; 10%) or medium amount close to sus420 stainless steel chromium system (gt; 10%)

B. hot working steel: medium C, a small amount of Cr

C. cold working steel: the global market reached us2billion yuan in 2010. High C Note: high speed steel: High C, a small amount of tungsten molybdenum vanadium system (even cobalt). Adding a small amount of chromium can increase the strength

9. Explanation of classification:

A. cold working steel: this kind of steel is used at room temperature. Due to its high hardness and wear resistance requirements, the carbon content belongs to high carbon steel (CGT; 0.8%), and even a small amount of tungsten molybdenum vanadium is added to help improve the wear resistance. In addition, high hardness must prevent embrittlement, so chromium (about 4mdash; 12%) is added to improve toughness and strength, which is often supplemented by manganese

B. hot working steel: the main requirements of this kind of steel are 500mdash; In the higher temperature environment around 850 ℃, the tungsten molybdenum vanadium series elements with high temperature resistance are equivalent to cold working steel. Because its wear resistance is not the main requirement, the carbon content only belongs to medium carbon steel (0.3mdash; 0.8%), and its further impact on toughness is reduced, so the chromium content slightly decreases (about 3mdash; 5.2%)

c. plastic steel: the wear resistance of the mold cavity surface is its main requirement, so it belongs to low carbon steel (CLT; 0.3%) to reduce its oxidation tendency, And add a medium amount of chromium or a small amount of nickel chromium to improve its corrosion resistance Selection of die steel

1 Forming method: you can choose from two basic material types:

A. hot working tool steel, which can withstand relatively high temperatures during die casting, forging and extrusion

b. cold working tool steel, which is used for blanking and shearing, cold forming, cold extrusion, cold forging and powder pressure forming

some plastics will produce corrosive by-products, such as PVC plastics. Factors such as condensation, corrosive gas, acid, cooling/heating, water or storage conditions caused by long-term shutdown will also cause corrosion. In these cases, die steel made of stainless steel is recommended

2. Mold size: pre hardened steel is often used for large-size molds, and overall hardened steel is often used for small-size molds

3. Mold usage times:

the mold used for a long time (gt; times) should use high hardness steel with a hardness of 48mdash; 65hrc。

the mold used for medium and long time (100000mdash; 1000000 times) should use pre hardened steel with a hardness of 30-45hrc

the mold used for a short time (lt; 100000 times) should use mild steel with a hardness of 160mdash; 2 50 hrc。

4. Surface roughness:

many plastic mold manufacturers are interested in good surface roughness; When sulfur is added to improve the metal cutting performance, the surface quality will decline, and the steel with high sulfur content will become more brittle

crl2

properties: high carbon and high chromium ledeburite steel has good hardenability and good wear resistance. Due to the maximum carbon content of 2.30% in the steel, the steel becomes hard and brittle, so the toughness of Chongnan is poor, it can hardly bear large impact load, is easy to embrittle, and is easy to form uneven eutectic carbides

purpose: it is used to manufacture cold stamping dies and punches that are subject to small impact load and require high wear resistance, and cold cutting cutting blades, drill sleeves, gauges, wire drawing dies, stamping dies, thread rolling plates, drawing dies, screw rolling dies, etc. for cutting hard and thin metals

production varieties: hot rolled steel, cold drawn steel, forged steel, hot rolled steel plate, cold drawn steel wire

crl2mo1v1

performance: high carbon, high chromium type ledeburite steel, drilling is not a necessary element when there are no special requirements. Because the content of molybdenum and vanadium is higher than Crl2MoV, the microstructure and grain size of the steel are further refined, which improves the hardenability, strength and toughness of the steel, and makes the comprehensive properties of the steel better

purpose: it is used to manufacture large and complex cold working dies requiring high wear resistance, such as cold cutting scissors, trimming dies, wire drawing dies, thread rolling dies, edging dies, and cold stamping dies and punches requiring high wear resistance

production varieties: hot rolled steel, forged steel, cold drawn steel, hot rolled steel plate, cold drawn steel wire

crl2mov

properties: high carbon and high chromium type ledeburite steel has good hardenability. The cross-section size can be completely quenched below 400mm, and has high wear resistance. The volume change during quenching is small. Its carbon content is much lower than that of Crl2 steel, and molybdenum and vanadium are added. Therefore, the hot workability, impact toughness and carbide distribution of the steel have been significantly improved

purpose: it is used to manufacture cold working dies with large cross-section, complex shape, high wear resistance requirements and bearing large impact loads, such as cold cutting scissors, trimming dies, edging dies, gauges, wire drawing dies, thread rolling dies, punching concave dies with complex shapes, deep drawing dies for steel plates, as well as cold stamping dies and punches requiring high wear resistance

production varieties: hot rolled steel, forged steel, cold drawn steel, hot rolled steel plate, cold drawn steel wire

cr5molv

properties: the alloy content is medium. Because it contains molybdenum and vanadium, the steel has good hardenability, uniform carbide distribution, certain impact toughness and good wear resistance

purpose: it is used to manufacture setting dies, drill sleeves, cold stamping dies and punches. It takes more than 90 days to transform the force from deformation into electrical parameters, trimming dies, thread rolling dies, thread rolling plates, gauges, etc

production varieties: hot rolled steel, forged steel, cold drawn steel, hot rolled steel plate, cold drawn steel wire

9mn2v

properties: compared with carbon tool steel, it has higher hardness and wear resistance, good hardenability and less deformation during quenching. Because the steel contains a certain amount of vanadium, the grain is refined and the overheating sensitivity is reduced. The heterogeneity of carbide is better than that of CrWMn steel

purpose: it is used to manufacture various precision measuring tools, templates, and punching dies, cold pressing dies, carving dies, material dies, scissors, taps, dies, reamers, etc. with smaller sizes as general requirements

production varieties: hot rolled steel, forged steel, cold drawn steel, hot rolled steel plate, cold drawn steel wire

small and medium-sized modules can be supplied according to the requirements of the demander

crwmn

performance under the condition of improving texture but not weight: it has high hardenability. Due to the addition of 1.20% - 1.60% (mass fraction) tungsten, carbides are formed, so it has certain hardness and wear resistance after quenching and low-temperature tempering. Tungsten helps to maintain fine grains, so that the steel has better toughness. This steel is sensitive to the formation of carbon, and this carbon makes the tool edge have the risk of spalling

application: cold working die steel widely used. It is used for manufacturing measuring tools, such as die, block gauge, sample column and sample sleeve, as well as high-precision stamping dies with complex shapes

production varieties: hot rolled steel, forged steel, cold drawn steel, cold drawn steel wire, silver bright steel wire, hot rolled steel plate, cold rolled steel plate

9crwmn

properties: low alloy cold working die steel has certain hardenability and wear resistance, small quenching deformation, uniform carbide distribution and fine particles

purpose: it is used to manufacture cold stamping dies with small cross-section and complex shape, as well as gauges, templates and other measuring tools

production varieties: hot rolled products, forgings, cold drawn products, cold drawn steel wires, cold rolled steel plates

Cr4W2MoV

performance: the performance of the new medium-sized alloy cold working die steel is relatively stable. Compared with the high alloy cold working die steel Crl2 and Crl2MoV, the service life of the die made of it is significantly improved. The eutectic carbide particles of the steel are fine, evenly distributed, and have high hardenability and hardenability, as well as good wear resistance and dimensional stability. However, the hot working temperature range of steel is narrow and the deformation resistance is large

usage: used for manufacturing various punching dies, cold heading dies, blanking dies, drawing dies, cold extrusion concave dies and thread rolling plates

production varieties: hot rolled products, forgings

small size modules can be supplied according to the requirements of the demander

6cr4w3mo2vnb

properties: High Toughness Cold working die steel, whose chemical composition is close to the matrix composition of high-speed tool steel, belongs to a matrix steel. Therefore, it has the high hardness and high strength of high-speed tool steel. Because the steel has no excess carbides, it has high toughness and fatigue strength. The steel contains 0.20%~0.35% (mass fraction) of niobium, which refines the grain and increases the grain refining temperature, thus improving the toughness of the steel and its process properties

usage: used for manufacturing cold extrusion dies, cold heading dies, screw punches, cold stamping dies, drawing dies, thread rolling plates, etc

production varieties: hot rolled products, forgings

some flat steel or other bars can be supplied according to the requirements of the demander

6w6mo5cr4v

performance: cold working die steel of low-carbon high-speed tool steel type has good hardenability, and has comprehensive properties such as high hardness, high wear resistance, high strength similar to high-speed tool steel, and also has better toughness than high-speed tool steel. The cold extrusion die made of this steel has a long service life. Due to the high molybdenum content in steel, its hot working temperature range is slightly narrow and its deformation resistance is large. This steel decarburizes easily

usage: used for manufacturing cold extrusion female dies, upper and lower punches, etc

production varieties: hot rolled products, forgings

small and medium-sized modules can be supplied according to the requirements of the demander. (end)

Copyright © 2011 JIN SHI