JPH0570893A - Heat resisting steel for heat resisting glass forming die - Google Patents

Abstract

PURPOSE:To provide a heat resisting steel for producing a heat resisting glass forming die in which strength at high temp. is improved and the occurrence of heat crack is prevented and also the service life of die is improved. CONSTITUTION:The heat resisting steel for heat resisting glass forming die has a composition consisting of, by weight, 0.1-0.4% C, 0.05-2.0% Si, 0.1-2.0% Mn, 10.0-15.0% Cr, 0.7-1.2% W, 0.7-1.2% Mo, 0.05-2.0% V, 0.001-0.10% B, and the balance Fe with inevitable impurities, or, at least one kind among 0.5-1.0% Ni, 0.1-6.0% Co, and 0.05-1.0% Ni is further incorporated into the above heat resisting steel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to heat resistant steel for heat resistant glass molding dies.

[0002]

2. Description of the Related Art Conventionally, 13Cr martensite stainless steel, SUH616, etc. have been used in heat-resistant glass molding dies used for manufacturing glass containers for cooking and the like, and also 13Cr martensite stainless steel. The improved steel of is also proposed. (Japanese Patent Publication Sho 57-5871
And JP-A-3-90539). When a heat-resistant glass molding die is manufactured using these heat-resistant steels, it is usually formed into a predetermined shape by a casting method.

[0003]

However, the heat-resistant glass molding die produced by using the conventional heat-resistant steel described in the above publication still does not have sufficient high temperature strength and heat check resistance. Further, since the conventional heat-resistant glass molding die is a cast product, there is a problem that the crystal grains are coarse and δ-ferrite is contained, and the life of the heat-resistant glass molding die is not sufficiently satisfactory. Therefore, it has been desired to develop heat resistant steels having further excellent heat resistance and heat check resistance and having a long life. The present invention has been made based on the above-described demands in the conventional technology. Therefore, an object of the present invention is to provide a heat-resistant steel for producing a heat-resistant glass molding die, which has improved high-temperature strength, suppressed generation of heat cracks, and improved mold life.

[0004]

Means for Solving the Problems As a result of investigations, the present inventors have found that when a heat-resistant steel having a specific alloy composition is forged, excellent toughness is imparted, and crystal grains become finer and segregation-free heat check It was found that a heat-resistant glass molding die having excellent properties was obtained, and the present invention was completed. That is, the heat-resistant steel for a heat-resistant glass molding die of the present invention has the following (1) or (2)
It is characterized by having any one of the alloy compositions.

(1) C: 0.1 to 0.4% by weight,
Si: 0.05 to 2.0%, Mn: 0.1 to 2.0%,
Cr: 10.0 to 15.0%, W: 0.7 to 1.2%,
Mo: 0.7 to 1.2%, V: 0.05 to 2.0%, and B: 0.001 to 0.10%, with the balance being Fe and unavoidable impurities.

(2) C: 0.1 to 0.4% by weight,
Si: 0.05 to 2.0%, Mn: 0.1 to 2.0%,
Cr: 10.0 to 15.0%, W: 0.7 to 1.2%,
Mo: 0.7-1.2%, V: 0.05-2.0%, B: 0.001-0.10%, and Ni: 0.5-.
1.0%, Co: 0.1-6.0% and Nb: 0.0
5 to 1.0% of at least one and the balance Fe and unavoidable impurities.

The reason for limiting the alloy composition in the heat resistant steel for the heat resistant glass molding die of the present invention is as follows. C: 0.1 to 0.4% C is an element effective for increasing the strength at room temperature and heat and improving the wear resistance. At least 0.1% is necessary for imparting strength, but if it exceeds 0.4%, it becomes hyper-eutectoid steel and the heat check resistance deteriorates due to the formation of huge carbides. The preferred range is 0.2-0.3
%. Si: 0.05 to 2.0% Si is an element that imparts oxidation resistance, and also acts as a deoxidizer. If the amount added is less than 0.05%, the effect as a deoxidizing agent is small, and if it exceeds 2.0%, the crystal grains become coarse and heat cracks are likely to occur. A preferable range is 0.2 to 0.6%.

Mn: 0.1 to 2.0% Mn is added as a deoxidizer, but if it is less than 0.1%, the effect is lost, and if it exceeds 2.0%, heat check resistance is high. Deteriorates. The preferred range is 0.5 to 1.0
%. Cr: 10.0 to 15.0% Cr is a basic element of the heat resistant glass molding die.
Cr is an element that has good oxidation resistance and heat resistance,
At least 10.0% is necessary, but if it exceeds 15.0%, δ ferrite is formed, and the heat check resistance tends to deteriorate, so the upper limit is set to 15.0%.

W: 0.7-1.2%, Mo: 0.7-1.2% W and Mo are strong carbide-forming elements and elements that improve high temperature wear resistance. It is necessary to contain at least 0.7%, but if it exceeds 1.2%, the formation of δ-ferrite is feared and the toughness decreases, so 0.7% is required.
Set within the range of up to 1.2%. V: 0.05 to 2.0% V is a carbide-forming element stronger than W and Mo, and improves strength at high temperatures and wear resistance. The effect is 0.
When it exceeds 2.0%, a large carbide is formed and the toughness decreases, so the upper limit is set to 2.0%. A preferable range is 0.2 to 0.4%.

B: 0.001 to 0.10% B is a trace additive element that is often used in heat-resistant steel, and is effective in improving high temperature strength and refining crystal grains. Is an essential element for property improvement. In order to improve high temperature strength and heat check resistance, at least 0.001% must be present.
If it exceeds%, cracking will occur during hot working, so it is necessary to set the above range. Ni: 0.5 to 1.0% Ni has the effect of imparting corrosion resistance and toughness to steel, and it is preferable that Ni is at least 0.5%, but if it exceeds 1%, the annealing hardness does not decrease, and , The stress cracking susceptibility after heat treatment becomes stronger. Further, Ni lowers the heat transformation point and is limited in the operating temperature, so the preferable range is 0.
5 to 0.7%.

Co: 0.1-6.0% Co is a strong austenite-forming element, and is an element useful for improving the high temperature strength.
The range of 6.0% is preferable. However, since Co is expensive, the upper limit is set to 6.0%. Nb: 0.05 to 1.0% Nb is a strong carbide-forming element similar to V, and makes the crystal grains fine to increase strength and toughness. For that purpose, at least 0.05% is required.
If it exceeds 0%, huge carbides are formed and the heat check resistance is deteriorated. The preferred range is 0.05-0.3%
Is.

The heat resistant steel for the heat resistant glass molding die of the present invention is
A heat resistant glass molding die having excellent high temperature strength and heat check resistance can be produced by forging. In order to produce the heat-resistant steel for the heat-resistant glass molding die of the present invention,
Although any method may be used, for example, a method in which an electrode melted in a high-frequency furnace is ingoted by an electroslag melting method is preferable because segregation can be reduced.
As a forging method, die forging is preferably used. The heat-resistant glass molding die formed is then subjected to quenching and tempering treatments. Quenching is preferably performed at a temperature of 900 to 1050 ° C. under oil cooling, and tempering is preferably performed at a temperature of 650 to 750 ° C. under air cooling. By quenching and tempering under the above conditions, the crystal grains become finer,
Further, the one having HB hardness of 280 to 310 is obtained.

[0013]

EXAMPLES Next, the present invention will be explained by examples. Examples 1 to 4 and Comparative Example A heat-resistant glass molding die was produced using heat-resistant steel having an alloy composition shown in Table 1. That is, the electrode obtained by melting in a high frequency furnace was remelted by the electroslag melting method, and the obtained steel ingot was forged. Forging, put up 1 / 2u,
A die having a desired shape was produced by die forging. Then
950 ° C: Quenching under oil cooling conditions, then 700
° C: Tempering was performed under air cooling conditions to obtain a mold product.

[0014]

[Table 1]

The mold products produced as described above were subjected to measurement of mechanical properties and heat check test. The results are shown in Tables 2 and 3. In addition,
The heat check test in Table 3 is a case where the operation of heating the die product from room temperature to 700 ° C. by high frequency heating and then returning to room temperature by water cooling was repeated 1000 times. In addition, with respect to the die product, the time until its disposal and the number of times the work for repairing during that time, that is, the work for scraping off the heat crack occurrence portion with a grinder were examined. The results are shown in Table 4. Further, a comparison was also made with respect to a die product obtained by casting the heat-resistant steel of the comparative example by an ordinary method. The survey results are also shown in Tables 3 and 4.

[0016]

[Table 2] From the results in Table 2, it can be seen that the heat-resistant glass molding die manufactured using the heat-resistant steel of the present invention has high mechanical strength and small crystal grains, and is advantageous in heat check resistance.

[0017]

[Table 3] From the results of Table 3, the heat-resistant glass molding die manufactured by forging using the heat-resistant steel of the present invention has a smaller number of cracks and a shorter crack length than those of the comparative example. It turns out to be excellent.

[0018]

[Table 4]

From the results shown in Table 4, the heat-resistant glass molding die manufactured by forging using the heat-resistant steel of the present invention requires a small number of repairs, a long time until disposal, and a heat resistance check. It turns out that it is excellent in sex.

[0020]

EFFECT OF THE INVENTION The heat-resistant glass molding die produced from the heat-resistant steel for heat-resistant glass molding die of the present invention has high mechanical strength, small crystal grains, and excellent heat-check resistance. Yes, and has a significantly longer life.

Claims (2)

[Claims] 1. C: 0.1 to 0.4% by weight, S
i: 0.05 to 2.0%, Mn: 0.1 to 2.0%, C
r: 10.0 to 15.0%, W: 0.7 to 1.2%, M
o: 0.7 to 1.2%, V: 0.05 to 2.0%, and B: 0.001 to 0.10%, and a heat resistance characterized by the balance Fe and unavoidable impurities. Heat resistant steel for glass molding dies. 2. C: 0.1 to 0.4% by weight, S:
i: 0.05 to 2.0%, Mn: 0.1 to 2.0%, C
r: 10.0 to 15.0%, W: 0.7 to 1.2%, M
o: 0.7 to 1.2%, V: 0.05 to 2.0%, and B: 0.001 to 0.10%, and Ni: 0.5 to 1.
0%, Co: 0.1-6.0% and Nb: 0.05-
A heat-resistant glass for a heat-resistant glass molding die, which contains 1.0% of at least one kind, and the balance Fe and unavoidable impurities.