JPS6339318A - Coating cylinder - Google Patents

Abstract

PURPOSE:To make the title cylinder suitable for a cylinder of a molding machine, which is used at high pressure, and capable with tendency of miniaturization, by selecting a think whose matrix part possesses sufficient hardness and strength. CONSTITUTION:Steel which can secure hardness of HR C22 or harder even if it is annealed from 800 deg.C after heating at 1,000-1,200 deg.C is used as a matrix. As for the steel which possesses the hardness of the HR C22 or harder even if it is annealed from 800 deg.C, a suitable thing can be found out of high alloy steel especially steel for a forging die and hot die steel. Steel having composition where the same contains one or two kinds out of 1.0-6.0% Cr, 0.01-0.50% Ni, 0.01-2.50% Mo and 0.10-1.50% V in addition to 0.10-0.50% C, 0.20-1.50% Si and 0.20-1.50% Mn, the rest is composed or Fe practically and Ceq which is expressed by an expression falls within a range of 1.65-1.95 is used for a material especially suitable for a matrix.

Description

[Detailed description of the invention]

1] purpose of invention

[Industrial application field]

The present invention relates to improvements in cylinders used in plus deck molding machines, particularly QJ extrusion molding machines and extrusion molding machines.

[Conventional technology]

The cylinders used in so-called engineering plastic molding machines, which have become popular in recent years, are made of a low melting point self-fusing alloy with corrosion and abrasion resistance on the inside so that they can withstand the harsh conditions of use. By centrifugal casting method]
-Many things are caused by dinging. Coding cylinders are manufactured by placing a self-fusing alloy in a cylindrical body, capping both ends, sealing it by welding, etc., placing it in a furnace, and heating it to 1000-1200'C to prevent the self-fusing alloy from melting. By the way, I took it out of the oven and put it straight away.
The process is carried out by cooling to approximately 800°C while rotating the self-fusing alloy in a rotary machine or at c-rotation, and when the self-fusing alloy solidifies, it is slowly cooled and returned to room temperature while avoiding cracks between the alloy layers and internal strain. In some cases, the base material is heated, and when it reaches a predetermined temperature, a separately molten self-fusing alloy is poured into it, both ends are covered, and the material is placed in a rotating machine. Generally, steel of about SCM440 is used for the base material from the viewpoint of workability. 1000-1200°C for SCM steel
The material is heated to a temperature of about 800'C, and then slowly cooled from a temperature of about 800'C, resulting in a state of over heat and annealing. Therefore, the tensile strength is 75 to 9T/
Only about M2 comes out, and the hardness is about HRC10.
Moreover, coarsening of the crystal grains is inevitable, and the Sh1fluvi impact value is 3 Kgf/cr? r or less. Injection molding pressure is 2,500 to 3,000 yen when molding engineering plastics, which are often intended to manufacture precision products.
There is a tendency to achieve a high level of OOOKfi f / ci, and along with this, miniaturization is often desired. For this reason, for example, the thread of the screw at the part where the nozzle head is attached to the cylinder ("I") must be stronger than before. It is also unsatisfactory due to the inability to cope with the trend of higher pressure and smaller size.More recently, with the advent of super engineering plastics, the molded part m can reach temperatures as high as 500'C, and the strength does not decrease even at the temperature of the bow. Is it possible to increase the hardness by heat treating the 1° base material required for the cylinder? Quenching is not recommended as it may cause cracking or bending between the BJ IJ cylinder and the inner surface]-Teink layer. I can't get any results.

[Problems to be solved by the invention]

The purpose of the present invention is to meet the above-mentioned needs by providing a plastic molding machine that has sufficient hardness and strength, has a low possibility of screw thread failure, can handle high pressure and miniaturization, and can be used safely even at high temperatures. Our goal is to provide coated cylinders. Structure of the Invention [Means for Solving the Problems] The coating cylinder (Jl) of the present invention is a plastic molded material in which the inner surface of the base material of the cylinder is coated with a self-fusing alloy having corrosion and wear resistance by centrifugal casting. In the coating cylinder of the machine, as the base material,
The steel is characterized in that it uses a steel that can maintain a hardness of H6022 or higher even after heating to 1000 to 1200'C and then slowly cooling from AOO'C. Suitable steels that have a hardness of H6022 or higher even when slowly cooled from aoo'c can be found among high alloy steels, particularly steels for forging molds, hot die steels, and the like. A particularly suitable monthly interest rate for mother H is C: 0.10~0°50%.
, Si: 0.20-1.50% and Mn: 0.
In addition to 20-1.50%, Cr:1. O~6.0%,
Ni: 0.01-0.50%, MO: 0', 01-2.
50% and V: 0.10-1°50% one or two
seeds, the remainder substantially consists of Fe, CeQ=C+1/B Mn +1/24Si +1/4
ONi 11150r'-+-1/4 Mo +1/1
The steel has a composition in which Ceq at 4V is in the range of 1.65 to 1.95. -〇- Table 5 shows more preferable materials, O~400'C, thermal expansion coefficient k, 12.5~1 II, Qx 1
0-6/'C 3°
If the material has a hardness of I-IRC 22 or higher, preferably about 30, when heated to 0 to 1200'C and then slowly cooled from ε300'C, it is possible to meet the requirements. The inventors have established. It is different from the conventional usage to cover such a material as the base material of the two l-7-ink cylinders according to the present invention, or after they are heated to 1000-1200'C, gradually The fact that the inventors discovered and utilized the fact that the alloy has a hardness of l-1, The functions of each component and the reason for limiting the composition range of the steel are as follows: C: 0.10
-0. 50% In order to ensure strength, 0.10% or more is required. However, if there is too much, the toughness will be drastically reduced.
Stop at 0.50%. Si: 0.20・~]950% Used as a deoxidizing agent, its effect is
3. On the other hand, the upper limit is set at 1.50% so as not to impair hot formability. Mn: 0.2% to 1.50% ゛Deoxidation and IB
In addition to having M sulfur action, addition of 0.20% or more is required to improve hardenability and provide strength. On the other hand, 1.5
Excessive addition of 0% or more increases the degree of segregation and reduces toughness. Cr: 1.0 to 6.0% Cr is an important component for obtaining hardenability, corrosion resistance, and strength, and its effects are hardly exhibited when the content is less than 1.0%. In addition, if 6.0% or more is added, hot 7111 II-
・j (disadvantageous for [Ni: 0.01 to 0.50%, MO: C,), 01 to 2
．． 50%, V2 0.10-1.50% All elements are elements with quenching 111 and an odd to high strength, and this effect C311, Ni is J, 0.01%, MO is 0.01
%, Vt, -1, 0, 10%''. From the flow restriction, NiL;I: 0.50%, M
otel, 2.50%, Vl, 1.1.50%, zo1
``L is set as the upper limit.2 COQ = C-+ 1/6 Mn 11/243
i +l//ION i -+-1/! iCr-1
-1/4 Mo-i 1/14V: 1.6b--
1,95 Ceq (7) 1 white is fiJ + A (use of 1 white + < 1 le Iko CL human value or preferably, 1
．． If it is less than 6!3, sufficient 4r hardness h) cannot be obtained. However, if the work is too rapid, cracks will form between the base material (A and the inner surface) and the wing layer when the base material is cooled, making it difficult to manufacture the desired tink cylinder. Therefore, 1
．． 95 is the upper limit. The selection of the coefficient of thermal expansion takes into consideration the relationship with the coefficient of thermal expansion of the self-fusing metal used in the 7l-ting. Thermal expansion coefficient of self-fusing metals in general

[jl, 12×10-6/
Since the temperature is around °C, it is preferable to use a matrix +Δ with a slightly larger expansion coefficient than this because it applies an appropriate compressive stress to the -ting layer when it is cooled from high temperature to room temperature. . On the other hand, since it is rather undesirable to apply too much stress, the thermal expansion coefficient of the matrix should be kept within the above-mentioned limit. [Comparative Example] A base material cylinder having a diameter of 120 m, an inner diameter of 36 mm, and a length of 1000 m was manufactured by machining using SCM/1.40 steel as 1.All. Inside this cylinder, a self-fusing alloy with the following alloy composition and a melting point of 1030'C was placed in a heating furnace, heated to 1150'C for 1 hour, taken out, placed in a rotating machine, and centrifuged. [by casting]~ting was performed. When the temperature dropped to 820°C, the rotation was stopped, and the product was placed in a slow cooling tank and slowly cooled to 20°C. The hardness and tensile strength of the base metal were measured after it was taken out and cooled down to normal temperature.
A value of 6 Kg f /mm2 was obtained. When this coating cylinder was attached to an actual injection molding machine and used, one of the screws in the nozzle head receptacle part developed a crack in the thread1.After using it for several months,
Furthermore, two of the pieces of wood were cracked, so I had to repair the threaded part. [Example] Using steel with the following alloy composition (%, residual Fe), a base material cylinder was manufactured using the same method as the comparative example. Hereinafter, a ]-ting cylinder was obtained in the same manner as in the comparative example. The hardness of the base material part is 1-IRC38, and the tensile strength is 12
It was 4 Kgf/mm2. This cylinder easily met the quality requirements of super engineering plastic molding machines used at high temperatures. Effects of the Invention The tink cylinder of the present invention has a base material portion with sufficient hardness and strength, so it is suitable as a cylinder for a molding machine used under high pressure, and can also cope with the trend toward miniaturization. Generally, preferred embodiments withstand use at high temperatures. Therefore, the cylinder of the present invention is suitable for use in injection molding machines and extrusion molding machines for engineering plastics and super engineering plastics.

Claims (3)

[Claims] (1) In a coating cylinder for a plastic molding machine in which the inner surface of a cylindrical base material is coated with a self-fusing alloy that has corrosion and wear resistance by centrifugal casting, the base material has H_RC2 even when slowly cooled from 800°C.
A coated cylinder characterized by using steel that can ensure hardness of 2 or more. (2) As base material, C: 0.10-0.05%, Si:
0.20-1.50% and Mn: 0.20-1.50
%, Cr: 1.0-6.0%, Ni: 0.01
~0.50%, Mo: 0.01~2.50% and V:
Contains 0.10 to 1.50% of one or more types,
The remainder essentially consists of Fe, Ceq=C+1/6Mn+1/24Si+1/40Ni
The coated cylinder according to claim 1, wherein a steel having a composition whose Ceq expressed as +1/5Cr+1/4Mo+1/14V is in the range of 1.65 to 1.95 is used. (3) The coated cylinder according to claim 1 or 2, in which steel having a thermal expansion coefficient of 12.5 to 14.0 x 10^-^6/°C at 0 to 400 °C is used as the base material. .