JPS61147853A - High-toughness ejector pin - Google Patents

Abstract

PURPOSE:To obtain the ejector pin for plastic having superior dimensional stability and high toughness by working a steel bar stock having specific composition into prescribed shape and by subjecting it to hardening and tempering under specific conditions. CONSTITUTION:The steel bar stock consists of, by weight, 0.5-0.8% C, 0.8-1.5% Si, 0.1-1% Mn, 5-6.9% Cr, 0.7-1.6% Mo, 0.4-1.2% W, 0.3-1% V, and the balance Fe with inevitable impurities. This bar stock is worked into prescribed shape, which is hardened from about 1,050 deg.C and tempered at about 500 deg.C to give about HRC60 hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic ejector and pin that have excellent dimensional stability and toughness during use.

Ejectors and pins for plastics must not undergo dimensional changes during long-term use, have sufficient toughness so as not to break during use, have high wear resistance, and have good seizure resistance. has been done.

Conventionally, as general-purpose plastic ejector pins, SKS 21 is quenched at approximately 850°C and then tempered at 180-200°C to achieve a hardness of around HRC60. is 200
If the temperature is around ℃, if used for a long time, the remaining austenite will decompose and expand, resulting in insufficient toughness, which may cause breakage in the case of small diameter pins. .

The present invention was made to solve these problems.The pin made of 5KS21 also has excellent toughness, moderate wear resistance, and can be used for long periods at around 200℃. It is an object of the present invention to provide an ejector pin that does not cause any dimensional change in the pin.

That is, the present invention provides C0. S~0.8%, si 0. s
~1.5%, Mn 0.1-1.0%, Cr 5.0
~6.9'16, h/L.

0.7~1.61 W0.4~1.2%, V0.3~1
．． This ejector is characterized by processing a steel bar consisting of O%, balance iron and some impurities, then quenching it at about 1050℃ and tempering it at about 560℃.
, 5KS21 Both pins and pins have extremely good toughness and relatively good wear resistance. In addition, since the tempering temperature is as high as 560℃,
Even when the molding temperature is around 200°C, there is no dimensional change during use.

Next, the composition-limited salt F of the extrusion pin of the present invention! Let me state 3.

C increases the hardness of martensite and is crbMo.

Forms carbide with WlV etc. to improve wear resistance,
If C is less than 0.5%, wear resistance will be insufficient;
If it exceeds this, the toughness decreases, so it was set at 0.5 to 0.8%.

Although Sl has the effect of increasing temper softening resistance,
If it is less than 0.8%, the effect is insufficient;
If it exceeds 0.8 to 1.5%, it becomes easier to decarburize.
limited to.

Mn has a deoxidizing effect, but if it is less than 0.1%, it has no effect, and if it exceeds 1%, the toughness deteriorates.
It was set at 1 to 1.0.

Cr improves hardenability and wear resistance, and increases temper softening resistance, but if it is less than 5.0%, wear resistance is insufficient, and if it exceeds 6,94 i, toughness deteriorates, so 5.
．． The range was 0 to 6.9 inches.

Mo improves hardenability and temper softening resistance, but 0
If it is less than 0.07 seconds, the effect will be small, and if it exceeds 1.6 inches, the toughness will deteriorate, so it is set to 0.7 to 1.6 inches.

W improves wear resistance, but if it is less than 0.4 mm, the effect is small, and if it exceeds 1 or 2% gold, the toughness decreases, so 0.
．． It was set at 4 to 1.2%.

(2) causes secondary hardening during tempering and improves wear resistance, but if it is less than 0.3%, it has no effect, and if it exceeds 1.0%, the toughness deteriorates, so 0.3 to 1
．． It was set to 0%.

Below, the effects of the present invention will be explained using examples. Table 1 shows the ejector and pin of the present invention and a comparative product (SKS 21
The chemical composition of ejector bisec made by

Table 2 shows the heat treatment and hardness applied to the ejector and pin.Table 3 shows the Dalian type wear test using the heat treated test pieces shown in Table 2 against 5CR420 annealed material. The ejector and pin of the present invention are SKS 21.
It can be seen that the wear resistance is almost the same as that of the ejector pin made by the manufacturer.

Table 4 shows the results of comparing the toughness of the IOR notch by performing a Charpy impact test. I understand.

Next, when an ejector pin with a diameter of 3.0 cm, which had the chemical composition shown in Table 1 and was subjected to the heat treatment shown in Table 2, was used in a plastic mold for 3 months, the result was 5KS.
The ejector and pin manufactured by No. 21 had an expansion of 0.15, but no dimensional change was observed in the ejector and pin of the present invention.

As explained above, the ejector pin of the present invention has C0.5-0.8'%, 810.8-1.5%, Mn
0, 1-1.0%, Cr 5.0-6.9%, Mo 0
．． 7-1.6%, WO 4-1.2%, 70.3-1.
After processing a steel bar consisting of 0% iron and some impurities into a predetermined shape, it is quenched at approximately 1050℃ and then quenched at 560℃.
It has been tempered to a hardness of around HuC60! D. The 5KS21 pin also has outstanding toughness.
However, it has the characteristic that there is no dimensional change even when used for a long time at around 200°C.

Table 1 IXz table Table 3 Table 4

Claims (1)

[Claims] 1% by weight, C0.5-0.8%, Si0.8-1.
5%, Mn0.1-1.0%, Cr5.0-6.9%,
Mo0.7-1.6%, W0.4-1.2%, V0.3
After processing a steel bar consisting of ~1.0% balance iron and some impurities into a specified shape, it is quenched at about 1050℃ and then tempered at about 560℃ to obtain H_RC60.
A high-toughness ejector pin featuring hardness at the front and back.