What is kovar alloy?

KOVAR alloy is an Iron-Nickel-Cobalt alloy with a density of 8.36g/cm3 and a linear expansion coefficient between 20 and 500℃ equal to that of glass and ceramics. Most metals cannot be sealed with glass because their thermal expansion rate is different from that of glass and the joints are liable to break when cooled. The nonlinear thermal expansion curve of KOVAR alloy can usually be matched with glass. It combines with glass through the intermediate oxide layer of nickel oxide and cobalt oxide, and the bonding strength depends on the thickness of the oxide layer. The reduction of cobalt makes the proportion of iron oxide lower and the oxide layer easier to melt and dissolve in the molten glass, allowing the joint to withstand a wide range of temperatures.

KOVAR alloy provides a tight mechanical connection between hard glass (e.g., borosilicate glass) and ceramics within a certain temperature range. Judging from the color of the interface, gray, gray-blue or grey-brown means a good seal, and black indicates that the alloy has been over-oxidized and weak bonding. Kovar alloy is suitable for glass/ceramic-metal seals in scientific equipment such as vacuum tubes (valves), microwave tubes, X-ray and microwave tubes, transistors, diode integrated circuits, etc.

Commercial brands for Invar alloy

 

AmericanCarpenterKovar®/Rodar®
Special MetalsNilo® K
FrenchAperam Alloys Imphy

(Imphy Alloys)

Dilver P1®
GermanVDM MetalsPernifer® 2918
JapanNIPPON YAKINNAS 29CO

 

Standards for Invar alloy

 

AmericanGermanChina
ASTM F15 K94610DIN 17745 Ni-Co 29 18

1.3981

YB/T 5231 4J29

 

Perm invar alloy composition

MaterialFeNiCoCSiMnPSCrCu
1.3981Rest29.017.0≤0.04≤0.2≤0.5//≤0.2≤0.2
K94610Rest28.0~30.016.0~18.0≤0.05≤0.3≤0.5////
4J29Rest28.5~29.516.8~17.8≤0.03≤0.3≤0.5≤0.02≤0.02≤0.2≤0.2

 

 

Typical linear coefficient of expansion(4J29)

TemperatureAverage coefficient of linear expansionā,10-6/℃
20℃~200℃5.9
20℃~300℃5.3
20℃~400℃5.1
20℃~450℃5.3
20℃~500℃6.2
20℃~600℃7.8
20℃~700℃9.2
20℃~800℃10.2

 

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What is invar alloy?

INVAR alloy, the abbreviation of Invariability, composed of64% Fe, 36% Ni and little other elements such as S, P, and C, has a very low linear expansion coefficient under 100 ℃, also known as low expansion steel, it’s firstly found by French physicist C.E.GuialmeI by 1896. The NVAR trademark was originally held by the French elfin alloy company and conformed to AFNOR NF A54, DIN 17745, ASTM F1684 and ASTM B753.

Most metals expand in volume when heated and contract when cooled, but for invar alloy, because of its ferromagnetism and the invar effect over a certain temperature range, has an extremely low coefficient of expansion, sometimes even zero or negative. Invar alloy is indispensable for manufacturing precision instrument due to the advantages of low expansion, has been widely used in the electronics industry and precision instrument industry and other areas where required special size like double metal materials, magnetic materials, such as measuring instruments with a fixture, astronomical telescope components, optical instruments, liquid, gas storage containers, antenna parts, FPD shielding frame, high precision printing with the framework, such as laser gyroscope.

 

Commercial brands for Invar alloy

FrenchAperam Alloys Imphy(Imphy Alloys)Invar®
AmericanCARPENTERInvar 36® Alloy
ATIATI 36™
Special MetalsNILO alloy 36
GermanVDM MetalsPernifer® 36
VACVACODIL 36
JapanNIPPON YAKINNAS 36
ItalyValbruna AGSG5

 

Standards for Invar alloy

CountryFrenchGermanAmericanChina
StandardsAFNOR NF A54-301, Fe-Ni36DIN 17745 Ni36,1.3912ASTM F1684 UNS K93603ASTM B753 T-36YB/T 5241 4J36

 

Perm invar alloy composition

GradesFeNiCSiMnP,maxS,maxCrCo
1.3912R35.0~37.0≤0.05≤0.3≤0.5////
K93603R36.0≤0.05≤0.4≤0.60.015b0.015b≤0.25≤0.5
T-36R36.0≤0.15≤0.4≤0.60.0250.025≤0.25≤0.5
4J36R35.0~37.0≤0.05≤0.30.2~0.60.02≤0.02//

 

Physical property

Density, g/cm3: 8.12

Hardness, HV: 140

Tensile strength, MPa: 500

Elongation, %: 30~45%

Modulus of elasticity, MPa: 134000

Cupping test value, mm: 9.8

Thermal conductivity, W·(m·K)-1:  0.109~0.134

Magnetoconductivity, mH·m-1: 2.04

 

Invar alloy coefficient of linear expansion(4J36)

The ratio of the length of metal at 0 ° c to its length at 1 ° c for each change in temperature is called the linear expansion coefficient.:

TemperatureThe average coefficient of linear expansion, ā,10-6/℃
20℃~50℃0.6
20℃~100℃0.8
20℃~200℃2.0
20℃~300℃5.1
20℃~400℃8.0
20℃~500℃10.0

 

More information about special alloys, contact LALLOY today!

What’s urea grade stainless steel?

Urea grade stainless steel is a kind of austenitic stainless steel specially for use of urea industry. Derivatives such as CO2, NH3, NH2COONH4, (NH2)2CO, etc. in the process of urea production are not highly corrosive when they exist alone, but the reactant formed when they are mixed together will cause strong corrosion to the equipment. Urea-methylammonium solution contains ammonium carbamate and ammonium cyanate, which has strong corrosion under high temperature and high pressure on the stainless steel, can destroy the stainless steel passivation film, so that contains 2% to 3%Mo of Cr-Ni Austenitic stainless steel is difficult to resist corrosion. In addition, the lining of the urea synthesis column, stripper and methylammonium condenser are easily corroded by methylammonium.

In the 1950s, Dutch company Stamicarbon proposed the use of 18-8 austenitic stainless steel under the condition of carbon dioxide and oxygen protection can be used for the urea industry, but there is still serious corrosion. With the development of ultra-low carbon stainless steel smelting technology, the purity of steel is greatly improved and finally formed into stainless steel for urea production. The chemical composition, microstructure and corrosion resistance of urea grade stainless steel are clearly defined, with the purpose of fully inhibiting the ferritic content in steel and obtaining the full austenitic structure, free of intermetallic phase precipitations as far as possible, so as to improve the corrosion resistance and selective corrosion ability of steel. All urea grade stainless steels are required to pass Huey test and selective corrosion test. In addition, metallographic inspection of the material is also required. No sigma phase and metal inclusions are allowed. These harsh test conditions make it difficult to meet the general stainless steel such as 316L.

310MoLN(S31050/725LN /1.4466/2Re69)and 316L mod(724L/316LN)are the most widely used urea grade stainless steels. 310MoLN is urea grade ultra-low carbon Austenitic stainless steel with a density of 7.9g/cm. Its corrosion resistance is similar to that of 904L steel, offers excellent corrosion resistance especially in ammonium carbamate and nitric acid. The 316L Modified stainless steel has low carbon content, extra-low silicon content and substantial higher molybdenum contents. 316L modified is designed for improved corrosion resistance properties in urea-carbonate environments.

The urea grade stainless steel offers excellent welding hot crack resistance and intergranular corrosion resistance, especially has good corrosion resistance for sulfurous acid, sulfuric acid, phosphoric acid, acetic acid, formic acid and chlorine salt, halogen, sulfite, has been successfully applied in urea production device such as a full cycle method of urea equipment, such as synthetic tower, such as high-pressure separator, also has been widely used in the pulp and paper, chemical fertilizers, chemical industry, pharmaceutical, synthetic fiber industry and other industries.

The effect of rare earth elements in cooper and its alloy

Rare Earth Elements (REE) is a group of metals for short, which including 17 kinds of Elements: 15 lanthanides, that is lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and two other Elements scandium (Sc) and yttrium (Y). Rare earth elements are almost insoluble in copper, but the addition of a little amount of rare earth elements, whether alone or mixed, is beneficial to the mechanical properties of copper and has little impact on the conductivity of copper. Such elements can form high melting point compounds with impurities such as lead and bismuth in copper and are distributed in grains as fine spherical particles to improve the high-temperature plasticity of copper alloys.

Experimental results show that adding 0.008% mixed rare earth or Y less than 0. L % to copper can significantly improve the mechanical and technological properties of copper. Copper alloys containing 0.01%~0.15% La have better mechanical properties, conductivity and softening resistance than Cu-0.15ag alloys, and have been widely used in electronics, petrochemical, metallurgy, machinery, energy, light industry, environmental protection, agriculture and other fields. Today here we will discuss the effect of rare earth elements on copper and its alloy.

 

Deoxidized and dehydrogenated

Strong affinity with oxygen, rare earth oxides offer good thermal stability, solid deoxidization products with copper in slag phase liquid surface is removed. Addition of rare earth metal an remove the small amount of oxygen in copper and its alloy obviously. Thermodynamic calculation show that the lanthanum, cerium, praseodymium, rubidium is more strong deoxidizer, their deoxidization ability at high temperature is significantly higher than aluminum and zirconium, also more than beryllium, magnesium, and calcium.

The copper solution is essentially insoluble in N2, CO2, and water vapor, but it’s opposite for O2, SO2, and H2. To hydrogen atoms dissolved in molten copper, rare earth elements are easy to react with hydrogen atomic state generated RH2 type RH3 and the stability of the hydride (R: rare earth element), which strongly exothermic reaction. Because of the small amount of hydrogen dissolved in copper, hydrogen absorbed by rare earth elements and the preference of R – H is a state of solid solution in copper and the alloy after adding rare earth elements, the hydrogen content will not reduce, but the rare earth has formed a stable solid solution, and hydrogen can be avoided under the condition of heating by hydrogen reduction of copper in copper oxide to produce steam to produce hydrogen embrittlement.

During copper processing, the addition of rare earth elements to the dissolved copper melt can quickly absorb and dissolve the hydrogen in the atomic state, and under certain conditions, the hydride with low density and easy to float on the surface of the copper solution can be generated, and under the action of high temperature, the hydrogen can be decomposed again, or it can be oxidized into the slag phase.

 

Removing impurities

Rare earth has strong chemical activity and can combine with many fusible components to form refractory binary or multiple compounds. They can interact with the low melting point elements sulfur, phosphorus, tin, and lead to combine into a variety of high melting point rare earth compounds or metallic compounds with various atomic ratios, such as Ce3Pb(1200℃) and BiCe3(1400℃), which will remain solid and slag together from the liquid copper, thus to achieve the purpose of removing impurities.

 

Structure refining

Rare earth elements can reduce or eliminate columnar crystals, refine grains and expand equiaxed crystal regions. The atomic radius of rare-earth elements (0.174nm-0.204nm) is 36% to 60% larger than that of copper (0.127nm). They react with some elements to form high-melting point compounds suspended in solution, which increase the number of grains, reduce the size and diffuse distribution, improve the plasticity and strength of the alloy, and reduce surface cracks and other defects.

For example, the addition of rare earth elements in C28000 copper alloy can refine the as-cast grains, which is conducive to the transition from neutral phase to carbon phase during recrystallization annealing, thus improving the mechanical properties of C28000 brass at room temperature.

 

Change the shape and distribution of impurities

Rare-earth elements can turn some of the strip, flake, or even block-shaped impurities in metals and alloys into punctate or spheres. For example, the inclusions of beryllium copper alloy are mostly irregular angular Cu2O and Cu2S. When the rare earth element increases to 0.05%, part of the inclusions are spheroidized; when it increases to 0.32%, all of the inclusions are spheroidized. Finally, it can make the impurities evenly distributed throughout the crystal and improve the comprehensive properties of the metal.

 

In summary, the addition of rare earth elements to copper and copper alloys can form high melting point compounds with oxygen, sulfur, lead, lead, etc. to remove impurities and purify; It can form a stable compound with hydrogen and dissolve in copper in the solid solution state, avoiding “hydrogen embrittlement”. The morphology and distribution of some impurities were changed to improve the metallographic structure, refine the grains, reduce or eliminate the columnar grains, and expand the equiaxed crystal region. These combined changes improve the property of casting, processing, mechanical, welding and corrosion resistance of copper and its alloys.

 

What is copper alloy 110?

110 Copper is UNS commercial pure grade number and its full name is C11000, also known as electrolytic tough pitch copper(ECP).  It offers excellent electrical conductivity, thermal conductivity and good processability. Usually speaking, copper 110 contains 99.99% copper and oxygen-free, because the trace oxygen is likely to cause “hydrogen embrittlement” and should not be processed (annealed, welded, etc.) and used in a reductive environment when heated (e.g. high temperature >370℃), but sometimes the content of oxygen is less strict and can be o.o4%  at most by agreement. C110 copper is readily cold worked and has much tighter limits on impurities than other grades.

Equivalent Materials:

  • ISO: Cu- ETP
  • EN: Cu- ETP; CW004A
  • DIN: ECu-58; 2.0065
  • BS: C101
  • JIS: C1100
  • GB: T2

 

Physical Properties

  • Tensile Strength:  32,000 psi
  • Yield Strength:   10,000 psi
  • Elongation:   55% (in 2″)
  • Melting Point (Solidus):  1949°F
  • Density (C110 Copper Alloy):   0.321-.323 lbs/cu in
  • Electrical Resistivity (Annealed):  10.3 Ω⋅cmil/ft @ 68°F
  • Electrical Conductivity (Annealed):  101 % IACS @ 68°F
  • Coefficient of Thermal Expansion:   0.0000098°F (68-572°F)

 

C110 Copper has a wide range of applications, specified for electronic applications such as components for vacuum devices, switches, interrupters, deposition units; components for superconductive magnets; electron tubes including anodes, glass-to-metal seals and linear accelerators. To learn more or to buy or C110 bar, contact us now!

What’s the difference between cold work tool steel and hot work tool steel?

Tool steel can be divided into these six groups: water-hardening, cold work, shock resisting, high-speed, hot work and special purpose according to its chemical composition and different applications. Cold work tool steel refers to the die steel used to deform or shape metal in cold conditions. It has high wear resistance, strength and toughness, strong bite resistance, softening ability under heat, etc. When cold working die steel is working, its working part is under great pressure, bending force, impact force and friction force due to great deformation resistance, so the failure of cold working die is usually because of the wear as well as the fracture, collapse force and deformation out of tolerance and failure in advance. Cold working tool steel includes die for cutting (blanking die, trimming die, punch, scissors), cold heading die and cold extrusion die, bending die and drawing die etc.

Hot work tool steel refers to the alloy tool steel maintain strength and hardness while exposed to prolonged elevated temperatures, such as hammer forging dies, hot extrusion dies and die-casting dies. Because the hot mold contact with hot metal directly, so there is a more severe demand requirement such as high strength, hardness and thermal stability, especially high thermal strength, thermal fatigue, toughness and wear resistance is required to ensure that the mold is enough to have a long service life. This is the main difference with cold mold working conditions. In addition, they differ from:

  • Different operating temperature.

Cold working tool steel works at room temperature (below 100℃). Hot work tool steel is in contact with hot metal or even liquid metal, so the surface temperature of the mold is very high, generally 350 ~ 700℃.

  • Different carbon and alloying elements

Cold tool steel usually has higher carbon content (1.45% ~ 2.30%) to meet the requirements of high hardenability and wear resistance. Medium carbon steel is sometimes used to improve the impact resistance and toughness of the die. Alloying elements such as Cr (11% ~ 13%), Mo, W, V are added to cold working die steels mainly to improve hardenability and wear resistance.

Hot-working die steel is medium carbon (0.3% ~ 0.6%). It has more requirements on red hardness, thermal conductivity and wear resistance, and the general requirements for hardness. Alloying elements such as Cr, Mn, Si, Ni, W, Mo, V can increase hardenability, oxidation resistance, wear-resistance and red hardness.

  • Different applications

Cold working tool steel is mainly used for making blanking die (blanking die, trimming die, punch, scissors), cold heading die and cold extrusion die, bending die and drawing dies.  Hot-working tool steel is mainly used in die casting.

4.Different tool steel codes

The series “A”, “O”, “D” belong to cold working tool steel, while the “H” series(H13) is the hot worked tool steel.

H13 tool steel heat treatment

Hot-working AISI H13 tool steel offers high hardenability, excellent wear resistance and hot toughness, has been widely used in hot forging dies, pressure dies casting tools, extrusion tools, hot shear blades, stamping dies, plastic mold and aluminum alloy die casting dies, is the most commonly used hot-worked die steel. The H13 steel made by electroslag remelting (ESR) process can effectively improve the low microstructure and densification of steel, and improve the isotropy of die steel. Compared with ESR process, the furnace refining H13 can save 20% ~ 30% of the production cost, is still the mainstream smelting method. Reasonable forging process and heat treatment process can improve the quality, performance and service life of H13 steel.

The heat treatment temperature and cooling method depend on the critical transition point and isothermal transition of the H13 tool steel. The following data you should know before the heat treatment of H13 steel:

1) Critical point: Ac1, 850~885 ℃, Ac3:910 ℃.

2) Cooling transition point: Ar1, 700℃; Ar3, 820 ℃; Ms, 335 ℃.

3) Austenitization temperature: 1 010 ℃


Annealing

In order to eliminate the stress of H13 steel forging, improve the structure, refine the grain, reduce the hardness for machining, annealing is a necessary process, generally is performed high temperature/isothermal spheroidization annealing: 860 ~ 890℃, heating and holding for 2h, cooling to 740 ~ 760℃ isothermal 4h, furnace cold to about 500℃ out of the furnace.

(1) the complete annealing process of H13 steel is :850~900℃, 3~4h.

(2) the isothermal spheroidizing annealing process: 845 ~ 900 ℃ by 2 ~ 4 h/furnace cooling + 700 ~ 740 ℃ by 3 ~ 4 h/furnace cooling, [40 ℃ / h, 500 ℃ from air cooling];

(3) H13 steel dies with higher quality requirements shall also be annealed to prevent white spot and the process cycle shall be longer;

(4) for molds with complex shapes, a stress-free annealing shall be conducted after rough machining :600~650℃, 2h/ furnace cooling; The carbide structure of large H13 steel forgings treated by conventional spheroidization annealing is extremely uneven, and the existence of severe intergranular carbide chains can be realized by multiple spheroidization annealing or austenitizing fast cooling (normalizing) respheroidization annealing

Quenching

H13 steel has good hardenability, for H13 forging thickness less than 150 mm, oil quenching can achieve uniform hardness, but it’s  easy to cause oxidation and decarburization and other defects deo to Mn, Si elements in the steel. It is recommended to use salt bath, controlled atmosphere heat treatment, vacuum heat treatment or coating to prevent decarburization.

The hardness of 54~55 HRC can be obtained by quenching at 1 030 ℃, and the grains begin to grow beyond 1 040 ℃. Therefore, the heat treatment temperature range of 1 030~1 040 ℃ is recommended. At the same time, special attention should be paid to pre-cooling to 20~30 ℃(950~980 ℃) above Ac3 when coming out of the oven to reduce stress concentration and avoid cracking.

Heating temperature 1020 ~ 1050℃, oil cold or air cold, hardness 54 ~ 58HRC;It is required that the quenching process specification of the die mainly hot and hard, the heating temperature is 1050 ~ 1080℃, the oil is cold, and the hardness is 56 ~ 58HRC.

Tempering

In order to eliminate the stress and improve the high temp toughness of H13 forgings must be tempered at high temperatures, secondary tempering can be used to improve the life of the die due to the good fire resistance and secondary hardening of the alloy elements in the steel. The tempering temperature (580±20 ℃) was used to obtain the hardness of 47~52 HRC. The microstructure after tempering is tempered martensite and a small amount of granular carbides.

Tempering should be done twice. When tempering at 500℃, the secondary hardening peak appears, with the highest tempering hardness and peak value around 55HRC, but the worst toughness. Therefore, according to the use of the mold needs 540 ~ 620℃ tempering is better. Quenching heating shall be preheated twice (600 ~ 650℃, 800 ~ 850℃) to reduce the thermal stress generated during heating.

 

Advantages of H13 tool steel made by ESR process

For high-quality tool steel, steel mills generally adopt the smelting processes such as furnace refining, vacuum treatment, vacuum smelting, powder spraying and electro slag re-melting to reduce the content of harmful elements such as oxygen, hydrogen and inclusions in steel. Hot-working AISI H13 tool steel offers High hardenability, excellent wear resistance and hot toughness, has been widely used in hot forging dies, pressure dies casting tools, extrusion tools, hot shear blades, stamping dies, plastic mold and aluminum alloy die casting dies.

The common smelting methods of AISI H13 tool steel include electric furnace smelting + electroslag remelting, ladle refining(LF) and electric furnace smelting + vacuum degassing(VD). As the name implies, electric furnace steel is the steel made by furnace including VD type ladle refining furnace, vacuum induction furnace and electric arc furnace and etc. Electroslag remelting (ESR) process can effectively improve the low microstructure and densification of steel, and improve the isotropy of die steel. The principle of ESR is: when the consumable electrode, slag and bottom water tank form a supply loop with the transformer through the short net, a current is sent from the transformer through the liquid slag. Because the slag resistance in the power supply circuit is relatively large, a large amount of heat is generated in the slag pool, making it in the molten state of high temperature. The slag pool’s temperature is much higher than the melting point of the metal, which gradually heats the end of the consumable electrode and melts it. The molten metal falls off the end of the electrode and enters the molten metal pool under the action of gravity. Due to the forced cooling of the water-cooled crystallizer, the liquid metal gradually forms an ingot.

Electroslag smelting process can effectively control the cleanliness and microstructure uniformity of H13 steel, which is an important link in the production of high-quality H13 steel. Relatively speaking, the cost of electric furnace smelting is low, and such refining methods as package LF+ VD can also produce H13 steel with low S and P content (≤0.003%S, ≤0.015%P). Except for some advanced special steel mills, the H13 steel produced by electric furnace smelting has low transverse toughness and cannot meet the standard of NADCA 207-2003 “north American die casting association H13 microstructure rating chart”. Compared with H13 electroslag steel, H13 furnace steel mainly has the following defects:

  1. Poor density and low purity;
  2. Severe annealing banding segregation and uneven annealing structure;
  3. After quenching and tempering, many liquid carbides remained unchanged; In the impact test, the place where the chain-like liquid carbide accumulates is easy to crack, and the fracture is characterized by horizontal streaks and low toughness.

Steel mill test results: ESR H13 tool steel has greater homogeneity and an exceptionally fine structure, resulting in improved machinability, polishability and high-temperature tensile strength. The transverse impact toughness of EAF H13 steel is equivalent to only 31% of the longitudinal, while the transverse impact toughness of ESR H13 steel is equivalent to 70% of the longitudinal. For the tool steels with special requirements, powder high-speed steels and high alloy die steels produced by powder metallurgy process can better improve the microstructure and properties of the steels.

Titanium and its alloy polishing methods

Titanium and its alloy have low density and excellent strength and weight ratio, good corrosion resistance and high mechanical strength, but expensive production cost. Titanium and titanium alloy grinding and polishing’s low efficiency make its microscopic structure change because the excessive severe cutting and polishing process will create a mechanical twin in the alpha phase.

At present, the methods of free abrasive grinding and chemical mechanical polishing are mainly used in the precision machining of titanium alloys. Grinding fluid is made by free silicon carbide or alumina abrasives, polishing fluid is a mainly strong acid, strong alkali or toxic chemical reagents, the free abrasives are difficult to control its movement trajectory, easy to leave deep scratches on the surface of the processing, reducing the processing accuracy. The handling of strong acids, strong bases and toxic chemicals is cumbersome, time-consuming and potentially hazardous to operators and the environment.

Early mechanical polishing processes were time-consuming, and almost all mechanical polishing methods used a polishing fluid containing an erosive agent in the final or two-step process. The electrolytic polishing methods can often get a better polishing surface, but the electrolyte brings a certain risk. This article here discusses the methods of grinding and chemical mechanical polishing to achieve super precision polishing of titanium alloys.

In the 1970s and 1980s, engineers Springer and Ahmed first published a paper on the polishing method of titanium and titanium alloys in 1984. This is the three-step sample polishing method. It is assumed that 320 grit paper is used to finish the sample grinding process, but this may not always be the case. If the sample is cut with an ultra-thin cutting piece or a grinding wheel cutting piece with appropriate bonding strength, the cutting surface is smooth and the damaged layer is minimal, 320grit is the ideal choice. If the cut surface is rough and the damaged layer is large, for example, if a band saw is used, then rougher sandpaper must be used and a certain amount of time must be spent to remove the damaged layer.

 

Springer, Ahmed titanium 3-steps polishing methods

  1. Grind, water cool with 320grit paper, grind for 2-3 minutes, remove the damage layer caused by cutting and make the surface of the sample flat. 320grit SiC sandpaper, water-cooled, rotate at 240 RPM, turn in the same direction, pressure: 27N (6lbs)/each sample until the sample is smooth. Note: removal of cut damage layer is the foundation of polishing, incomplete removal can directly affect the experimental results.
  2. Rough polishing, pre-apply 9 mm METADI® diamond polishing paste on TEXMET® polishing cloth with holes, use distilled water as cooling lubricant, and polish for 10~15 minutes. Rough polishing process: 9 mm METADI diamond polishing fluid + METADI polishing lubricant, polishing surface with ultra-pad ™, 120 RPM, reverse rotation, pressure: 27N (6lbs)/each sample, time: 10min.
  3. Finish polishing, using MICROCLOTH® or MASTERTEX® polishing cloth, adding MASTERMET® silica suspension polishing fluid and polishing for 10-15 minutes. Final polishing process: on the polished surface of MICROCLOTH, use MASTERMET silica polishing fluid, rotate at 120 RPM, reverse rotate, pressure: 27N (6lbs)/sample, time: 10min.

 

Müller titanium 3-steps polishing methods

  1. P500 sandpaper, water-cooled, rotating speed 300 RPM, pressure 16.7n (3.75lb) on each sample, preparation time until all samples are smooth.
  2. P1200 sandpaper was water-cooled at a speed of 300 RPM, a pressure of 16.7n (3.75lb) on each sample, and a 30S preparation time. Note: the specific time is determined according to the actual polishing situation, and the time parameters are only for reference. Usually, manual polishing is used for polishing, so the parameters may vary depending on the equipment.
  3. Synthetic non-pile polishing cloth + silica suspension polishing fluid containing chemical etchant, polishing machine speed is 150 RPM, polishing time: pressure on each sample is 33N (7.5lb) for 10 minutes, pressure on each sample is 16.7n (3.75lb) for 2 minutes, and pressure on each sample is 8N (2lb) for 1 minute.
  4. Polishing agent: 260ml SiO2+40ml H2O2 (concentration 30%),1mlHNO3 + 0.5ml HF.The P500 and P1200 grit sizes of FEPA correspond to ANSI/CAMI 320/360 and 600 grit, respectively.

Steel introduction: PM ASP® 2030 Steel

The ASP® is a range of powder metallurgy high-speed steel brands form Erasteel, a subsidiary of France Eichmann group. The ASP® steels are suitable for a wide range of tooling and component applications like cutting tools, cold work tools, saws & knives, automotive components and wear-resistant components. The steel mainly includes: ASP®2005, ASP®2017, ASP®2023, ASP®2030, ASP®2052 and ect, they can be good at different applications such as ASP®2055 with cobalt for gear cutting, ASP®2030 for taps and ASP®2005 for the cold work. Today we will introduce ASP® 2030 steel for you, if interested in, please read on.

 

Features

HSS ASP2030 is characterized by good high wear resistance, high compressive strength and high hardness, overall hardening and heat treatment dimensional stability and resistance to reignition, especially suitable for use in high load forming dies and multi-blade tools.

 

Standards and Equivalent Brands

AISIENW.Nr.
M3:2+CoHS 6-5-3-81.3244
ErasteelASP®2030
ASSABVANADIS 30
BöhlerS590
CrucibleCPM Rex 45
HitachiHAP40
DAIDODAP 540,DEX40
SanyoSPM30

 

Chemical Composition

CCrMoWCoV
1.284.25.06.48.53.1

 

Hardness of delivery

DeliverySoft annealingCold drawCold rolled
Hardness, HB≤300≤320≤320

 

Physical property

Temperature20℃400℃600℃
Density, g/cm3  [1]8.17.97.9
Elasticity modulus, kN/mm2  [2]240214192
Thermal expansivity, per℃ [2]11.8×10-612.3×10-6
Thermal conductivity, W/m℃ [2]242827
Specific heat, J/kg℃ [2]420510600

Note: [1]: Soft annealing; [2]: Quenching at 1180℃, tempering at 560℃, 3×1H

 

Heat treatment

  • Soft annealing in shield gas in the temperature of 850 ~ 900℃ for 3 hours, then slow cooling 10℃ to 700℃ per hour, followed by air cooling.
  • De-stress is between 600℃ and 700℃ for about 2 hours, then slowly cool to 500℃.
  • Quenching in the shielding gas, preheating at 450 ~ 500℃ and 850 ~ 900℃ respectively, austenitizing at the required hardness suitable temperature, slow cooling to 40 ~ 50℃.
  • It is recommended to temper 3 times at 560℃ for at least 1 hour each time, cool to room temperature (25℃) in the process of tempering.

 

Surface treatment

ASP2030 is a good substrate material for PVD (physical coating) and CVD (chemical coating). If nitriding is required, 2 to 15 m thick permeable layer or steam tempering is recommended.