JP2006315357A - Combined cylinder for molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combined cylinder for a molding machine having sufficiently long useful life of a cylinder and excellent in abrasion resistance even if a resin containing a large amount of a thermosetting resin, a mineral and a glass fiber is molded. <P>SOLUTION: In the combined cylinder for the molding machine forming a coated layer excellent in abrasion resistance on the inner face of an external cover including a steel material, the coated layer comprises a Fe base alloy containing, by mass%, C of 1.0 to 4.0%, Si of 0.2 to 4.0%, Mn of 0.1 to 5.0%, Ni of 4.0 to 10.0%, Cr of 10.0 to 25.0%, Mo of 9.0% or less and V of 4.0 to 15.0%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a compound cylinder for a molding machine that is used for injection or extrusion molding of plastic or the like, and in which an inner surface of a cylinder outer cylinder is coated with a wear-resistant corrosion-resistant alloy.

  The injection molding method is a method capable of molding a plastic product at high speed and with high precision, and is widely used for manufacturing various components such as automobile products and home appliances. The compound cylinder for molding machines constitutes the injection device for injection molding machines and extrusion molding machines, and requires performance that does not corrode or wear against molding resin, and does not wear against sliding of plungers and screws. Is done.

  Conventional composite cylinders for molding machines include those made of nitrided steel and those in which a Co-base alloy, Ni-base alloy, and Fe-base alloy are lined on the inner surface of an outer cylinder made of a hollow cylindrical steel material. In recent years, molding resin materials containing reinforcing materials and additives have been increasing, and therefore composite cylinders for molding machines having further corrosion resistance and wear resistance are required.

  For example, in Patent Document 1, C: 1.0 to 3.0%, Si: 0.1 to 4.0%, Mn: 0.1 on the inner surface of a cylinder outer cylinder made of a steel material in weight percent. -2.0%, Ni: 2.0-7.0%, Cr: 1.0-20%, Mo: 1.0-7.0%, B: 1.0-4.0%, V: A cylinder for a molding machine is disclosed in which an Fe-based alloy containing 0.01 to 3.0% is lined by centrifugal casting. This Fe-based alloy has been improved in corrosion resistance and wear resistance by crystallizing carbide and boride as primary crystals with high hardness and excellent corrosion resistance in the structure of the primary crystal part by controlling specific components. .

  In Patent Document 2, C0.01 to 0.5% by weight, Si2.5 to 10.0, Mn 0.5 to 1.5%, Cr5.0 to 10.0%, B2.0 to The inner surface of the cylinder base material is coated with a Ni-based alloy containing 6.0%, Co 5.0 to 35.0%, Fe 25.5% or less, the balance being Ni and inevitable impurities, and precipitation strengthening by precipitates. A cylinder for a molding machine is disclosed. This is because the inner surface of the cylinder is coated with a Ni-based alloy by centrifugal casting, and then heat treated to precipitate precipitates. Even if the Co content is reduced, the wear resistance and corrosion resistance are not deteriorated, and it is inexpensive. Can be manufactured.

JP 2001-279369 A Japanese Patent Laid-Open No. 9-104047

  In conventional cylinders made of nitrided steel, the strength of the cylinder against the injection pressure is not sufficient, and when molding resin containing additives, etc., the corrosion resistance and wear resistance of the cylinder are not sufficient. There was a problem that the inner surface of the cylinder deteriorated and could not be used as a cylinder.

  For this reason, some Co-base alloys, Ni-base alloys, and Fe-base alloys having corrosion resistance and wear resistance are lined on the inner surface of the cylinder by the centrifugal casting method or the HIP method.

  However, in recent years, when a thermosetting resin or a resin containing a large amount of minerals or glass fibers is molded, the conventional Co-based alloy, Ni-based alloy, or Fe-based alloy has a problem that the life of the cylinder is not sufficient.

  In view of the above problems, the object of the present invention is for a molding machine excellent in wear resistance with a sufficiently long useful life of a cylinder even when a thermosetting resin, a resin containing a large amount of minerals and glass fibers is molded. It is to provide a composite cylinder.

  The present inventors have formed a coating layer in which MC carbide is uniformly dispersed mainly on the inner surface of a cylinder outer cylinder for a molding machine, so that the useful life of the cylinder is sufficiently long. I found a compound cylinder.

That is, the hollow cylinder-shaped composite cylinder for a molding machine of the present invention is a composite cylinder for a molding machine in which a coating layer having excellent wear resistance is formed on the inner surface of an outer cylinder made of a steel material. % By mass
C: 1.0-4.0%, Si: 0.2-4.0%,
Mn: 0.1 to 5.0%, Ni: 4.0 to 10.0%,
Cr: 10.0-25.0%, Mo ≦ 9.0%,
V: 4.0-15.0%
It is characterized by comprising an Fe-based alloy containing

  In the present invention, the coating layer further contains, by mass%, any one or more of W <0.2%, Co ≦ 5.0%, Nb ≦ 10.0%, and Al ≦ 3.0%. Features.

  The composite cylinder for a molding machine of the present invention is a composite structure in which a coating layer is formed on the inner surface of an outer cylinder made of a steel material, and mainly by forming a coating layer in which MC carbides are uniformly dispersed, Improved corrosion resistance and wear resistance.

  The reason for limiting the content range (% by mass) of each element of the coating layer formed on the inner surface of the composite cylinder for a molding machine of the present invention will be described.

C: 1.0-4.0%
C is necessary for the formation of carbide for improving the wear resistance and the improvement of the hardness of the base during quenching and tempering by solid solution in the base. C produces a hard carbide that contributes to an improvement in wear resistance. If C is less than 1.0%, there is little crystallization of hard carbide effective for improving the wear resistance, and there is a shortage of C dissolved in the matrix, so that sufficient matrix hardness cannot be obtained even by quenching. On the other hand, if it exceeds 4.0%, the hard carbide becomes coarse and the amount of crystallization becomes excessive, and the toughness tends to deteriorate.

Si: 0.2-4.0%
The content of Si is preferably 0.2 to 4.0%. Si acts as a deoxidizer and is contained in a hard carbide by replacing it with elements such as W and Mo. Therefore, it is effective for saving expensive elements such as W and Mo. is there. If Si is less than 0.2%, the deoxidation effect is insufficient and casting defects are likely to occur. If it exceeds 4.0%, embrittlement tends to occur.

Mn: 0.1 to 5.0%
The Mn content is preferably 0.1 to 5.0%. Mn has a deoxidizing action like Si. When the Mn is less than 0.1%, this deoxidation action is deteriorated. When Mn exceeds 5.0%, oxidation resistance is inferior. Further, segregation of carbides occurs and the strength deteriorates. The content of Mn is preferably 0.15 to 5.0%, and more preferably 0.2 to 5.0%.

Ni: 4.0 to 10.0%
The content of Ni is preferably 4.0 to 10.0%. If the content is less than 4.0%, the martensite of the metal structure is likely to occur. On the other hand, if the content exceeds 10%, segregation occurs and the base becomes soft. Moreover, corrosion resistance is also improved by mix | blending 4.0% or more.

Cr: 10.0-25.0%
The Cr content is preferably 10.0 to 25.0%. This is because if the content is less than 10.0%, stable austenite cannot be crystallized and the corrosion resistance is lowered. On the other hand, if it exceeds 25.0%, segregation occurs and the strength is deteriorated. Become.

Mo ≦ 9.0%
The Mo content is preferably 9.0% or less. Mo is effective for stabilizing the base, and when Mo is contained, if its content exceeds 9.0%, the crystallization of the hard carbide is made unstable and the corrosion resistance is deteriorated.

V: 4.0 to 15.0%
V forms a hard MC-based carbide, M4C3-based carbide, which contributes most to the improvement of wear resistance. When V is less than 4.0%, the generation of carbide is small and the wear resistance is insufficient. If V exceeds 15.0%, MC and M4C3 carbides are aggregated and segregated during solidification to cause brittle deterioration, which is not preferable. A more preferable V content is 8.0 to 12.0%.

W <0.2%,
Co ≦ 5.0%,
Nb ≦ 10.0%,
Al ≦ 3.0%
About W, Co, Nb, and Al, what is necessary is just to mix | blend suitably according to purposes, such as abrasion resistance and oxidation resistance. Even if these are blended singly, there is an effect, but a more excellent effect can be obtained by blending them in combination.

  Furthermore, it is desirable that the composite cylinder for a molding machine of the present invention is obtained by metal-bonding a coating layer on the inner surface of the outer cylinder by a centrifugal casting method. By performing the centrifugal casting method, the coating layer can be bonded to the inner surface of the outer cylinder with a fine and uniform structure and a uniform thickness.

  Further, in order to further improve the corrosion resistance, the surface of the formed coating layer is subjected to nitriding treatment to form a nitriding treatment layer, or further, immersion treatment is performed in a molten salt containing metal Cr powder, A film layer made of Cr nitride or Cr carbonitride may be formed.

  Examples of the composite cylinder for a molding machine according to the present invention will be described below. FIG. 1 shows a schematic cross-sectional view of a composite cylinder for a molding machine according to the present invention in which an Fe-based alloy coating layer is bonded to the inner surface of a steel outer cylinder. In FIG. 1, a molding machine composite cylinder 1 is configured by welding a coating layer 3 made of an Fe-based alloy on the inner surface of a steel outer cylinder 2.

  The outer cylinder 2 has a hollow cylindrical shape and is made of general structural steel. The outer cylinder 2 has an outer diameter of 120 mm, an inner diameter of 39 mm, and a length of 850 mm. An iron plate was welded and closed on the rear end side of the outer cylinder 2, and the outer cylinder 2 was set in the longitudinal vertical direction with the rear end side down, set in a heating furnace, and then heated to 1100 ° C.

  The coating layer is, in mass%, C: 2.4%, Si: 2.4%, Mn: 2.5%, Ni: 5.9%, Cr: 15.4%, Mo: 0.2%, V: An ingot having a component of 10.9% was melted at 1540 ° C., and the molten metal was cast from the injection port side of the outer cylinder 2 heated to 1100 ° C. Then, a stopper was quickly driven into the hole on the injection port side and moved to a centrifugal casting machine. The centrifugal casting machine was set so that the longitudinal direction was horizontal. The centrifugal casting machine was actuated and rotated at 1000 rpm. When the outer surface temperature of the outer cylinder 2 reached 600 ° C., the rotation was stopped and put into a slow cooling furnace.

  After stopping the rotation, it was cooled to a predetermined temperature and quenched. Then, the composite cylinder material for molding machines was obtained by performing strain relief annealing and annealing 3 times at 400-600 degreeC. Subsequently, the outer peripheral surface, end surface, and inner surface of the cylinder material were finished to predetermined dimensions.

  When the composite cylinder for a molding machine of the present invention thus manufactured was installed in an actual injection molding machine and used for injection molding of a resin containing a large amount of glass fiber, a conventional Co-based alloy, Ni-based alloy, Fe Compared to a cylinder whose inner surface is coated with a base alloy, it has excellent wear resistance and can be used stably for a long time.

  According to the composite cylinder for a molding machine of the present invention, it is possible to provide a composite cylinder for a molding machine that is superior in wear resistance compared to a conventional cylinder in which a Co-base alloy, Ni-base alloy, or Fe-base alloy is coated on the cylinder inner surface. I was able to.

It is sectional drawing which shows the compound cylinder for molding machines which concerns on the Example of this invention.

Explanation of symbols

  1 Compound cylinder for molding machine, 2 outer cylinder, 3 coating layer

Claims (2)

A composite cylinder for a molding machine in which a coating layer excellent in wear resistance is formed on the inner surface of an outer cylinder made of a hollow cylindrical steel material, the coating layer being in mass%,
C: 1.0-4.0%, Si: 0.2-4.0%,
Mn: 0.1 to 5.0%, Ni: 4.0 to 10.0%,
Cr: 10.0-25.0%, Mo ≦ 9.0%,
V: 4.0-15.0%
A composite cylinder for a molding machine comprising an Fe-based alloy containing The coating layer further includes at least one of W <0.2%, Co ≦ 5.0%, Nb ≦ 10.0%, and Al ≦ 3.0% by mass%. Item 2. A composite cylinder for a molding machine according to Item 1.