SU908913A1 - Martensite ageing steel - Google Patents

Description

I

The invention relates to metallurgy, in particular to martensite-aging steels used for making molds, working under pressure when casting non-ferrous metals.

Closest to the proposed is maraging steel TV, containing, wt.%:

Carbon0.003 - 0.03

Nickel -15 -17,5

Vanadium4 8.5

Titan, 1 -1.3

Cobalt0.1 - 9.0

Molybdenum1.1 - 7.5

IronErest

The disadvantages of the known steel are its low temperature resistance and low resistance to oxide.

The purpose of the invention is to increase the heat resistance of steel.

The goal is achieved by the fact that maraging steel containing iron, carbon, nickel.

molybdenum, vanadium, titanium, dopon

It contains yttrium in the following ratio of components, wt.%:

Carbon0.005 - 0.05

Nickel15-17

Titan0.9 - 1.5

Molybdenum 0.5 - 1.0

Vanadium 0.3 -1.0

Yttrium0.005 - 0.1

Iron

Rest

Content of impurities, wt.%:

Manganese up to 0.3

Silicon up to 0,2

Aluminum up to 0,2

Copper up to 0.3

ChromeDo 0.2

The effect of alloying elements on the properties of steel is as follows: nickel provides for the formation of martensitic structure when cooled in air, reduces the solubility limit of a number of elements (titanium, molybdenum, etc.), increases the resistance 39 to brittle fracture in a high strength state amounts of 0.5–2.0% in steel containing titanium increases its ductility and toughness; titanium is the most effective element, hardening high-strength martensite steel, vanadium acts like molybdenum, promotes hardening of steel with aging, yttrium increases the heat resistance of steel, increases the resistance to oxidation.The limits of alloying elements are determined by the nature of their influence on the structure and properties of steel.The nickel content from 15 to 17% is determined by obtaining the structure of carbon-free martensite, having high ductility. When the nickel content is 15%, the ductility after aging drops slightly, an increase in the nickel content of 7% does not give an increase in ductility. Molybdenum is introduced into steel to increase ductility from 0, 5 to 1.0%, it prevents the strengthening of the hardening phases at the grain boundaries. When vanadium is present in steel, an increase in the molybdenum content of 1.0% 34 does not affect ductility. When the content of molybdenum 0.5% ductility decreases. Yttrium in the amount of not less than 0.005% contributes to the refining of steel, increases its casting properties, increases the heat resistance. The introduction of yttrium in an amount of more than 0.1% leads to a drop in plasticity due to the formation of an excess phase. In quantities of less than 0.005%, yttrium does not have any effect on steel. The steels of the four compositions were smelted in an open induction furnace with a capacity of 60 kg. The compositions of the steels are given in table.1. In tab. Figures 2 and 3 show the mechanical properties of the investigated steels at room temperature and temperature of 700 ° C, which corresponds to the working surface of the mold when pouring liquid brass. Tests show that the introduction of yttri increases the heat resistance of the proposed steel compared to that known approximately by 2 times. Table

JKf AM J

Steel

table 2

Since, in order to increase the heat resistance, it additionally contains yttrium in the following ratio of components, wt.%:

Carbon 0.005-0 05 Nickel15 - 17

That blitz 3

Sources of information) taken into account in the examination

1. USSR author's certificate 551404, cl. C 22 C 38/14, 1977.

Claims (1)

Claim Maraging steel containing iron, carbon, nickel, molybdenum, vanadium, titanium, characterized in that, in order to increase heat resistance, it additionally contains yttrium in the following ratio of components, wt.%: Carbon 0.005 - 0.05 Nickel 15-17 Molybdenum 0.5 - 1.0 Vanadium oh s - 1.0 Titanium 0.9 - 1.5 Yttrium 0.005 - 0.1 Iron Rest