SU711155A1 - Casting steel - Google Patents

Description

This invention relates to the metallurgy of steel and foundry and can be used to make superior quality castings. Known cast steel 20Kh8VL, containing, wt.%: Carbon0.15-0.25 Silicon0.3-0.6 Manganese 0.3-0.5 Chromium 7.5-9 Tungsten1.25-1.75 Nickel not more than 0.5 Medne more than 0.3 Serane more than 0.035 Phosphate more than 0.04 Iron SEC: total 1. The nominal values of the mechanical properties of the steel after annealing at 950 normalization at 950s and the subsequent tempering at 680-720 ° C are at the level of the properties of steels 20X5TL and 20X5ML. The disadvantages of the known steel are relatively low mechanical properties and density, not both baking high tightness of castings made from it. The purpose of the invention is to develop cast steel for castings with increased density and tightness, as well as improved mechanical properties with high corrosion resistance under conditions of highly sulfur-containing petroleum media. This goal is achieved by the fact that the proposed cast steel additionally contains aluminum, vanadium, calcium, magnesium, rare earth metals and nitrogen in the following ratio of components, wt.%: The metal is smelted in a 60-kg induction furnace of the type LPZ-67.

The chemical compositions of the steel produced are listed in Table 1. Results

Research steel density and mechanical properties are given in table 2,

Table 1

Thermal treatment of steels of experimental compositions consists of annealing at 950 ° С, normalization during and tempering at 680-700 ° С,. From the results it follows that the density of the steel after microalloying increases from 7.73 to

7.76 g / cm. Increasing the density of the steel makes it possible to increase the test pressure to 800 atm when testing the casting for water density. At the same time, the mechanical properties of the steel increase.

Studies on corrosion resistance show that its level in the proposed steel corresponds to the level known - 20X8VL. Higher level of all comp. | The properties of the proposed steel pos.Table

It is necessary to improve the quality and reliability of critical castings and recommend it for wide industrial use in chemical engineering.

Claims (1)

The invention of the Foundry steel containing carbon, silicon, manganese, chromium, tungsten, nickel, copper and iron, characterized in that, in order to improve the mechanical properties, density and tightness of castings, it additionally contains aluminum, vanadium, calcium, magnesium, rare earth metals and nitrogen in the following ratio of components, weight,%: Carbon 0.15-0.25 Silicon0.3-0.6 0.3-0.5 7.5-9 1.25-1.75 0.1-0.5 0.1-0.3 0.01-0.1 0.01-0.2 0.005-0.08 Magnesium 0.005-0.05 Rare earth metals. о; о1-о, 1 Nitrogen 0,005-0,06 Iron Else Sources of information, rintye taken into account during the examination 1. Steel 20Kh8VL, GOST, 2176-67.