SU943317A1 - Steel composition - Google Patents

Abstract

The steel has the compsn. (by wt.) 0.08-0.14% carbon, 0.10-0.37% silicon, 0.6-1.4% manganese, 1.7-2.7% mickel, 0.4-0.7% molybdenum, 0.03-0.07% vanadium, 0.02-0.07% aluminium, 0.005-0.012% nitrogen, 0.008-0.015% phosphorus, 0.003-0.008% arsenic, 0.001-0.005% tin, 0.005-0.15% calcium, balance iron, the phosphorus content multiplied by the sum of the nickel and manganese contents being less than 0.037%. The steel is esp. useful for welded structures subjected to pressure and temperatures of up to 450 deg.C. e.g. the pressure vessels of nuclear power plant.

Description

(S) STEEL

one

The invention relates to metallurgy, in particular to steels that can be used in power engineering for the manufacture of welded structures operating under pressure at temperatures up to, for example, pressure vessels of nuclear power plants.

Known steel tO containing.

weight.

0.08-0.11

Carbon

0.17-0.37

Silicon 0.6-1, V

Manganese

1.7-2.7

Nickel 0.35-0.6

Molybdenum

0.03-0.07

Vanadium

0.02-0.07

Aluminum

0,005-0,012

Nitrogen

Rest

Iron

Steel may contain impurities.

weight.:

Up to 0.5 Chromium To 0.2 Copper

Sulfur up to 0.02

PhosphorUd 0,013

The disadvantage of steel is the tendency to embrittlement in the process of long exposures at 350-5p | increasing with the approach of nickel and manganese concentrations to the upper limits. WITH.

The purpose of the invention is to reduce the tendency of steel to embrittlement in the process of exposure at 350-50 s.

to

The goal is achieved by the fact that steel additionally contains mouse, tin and calcium in the following ratio of components, wt.%: Carbon 0.08-0.11

ts

Silicon0.10-0.37

Manganese 0.6-1,

 Nickel1.7-2.7

 Molybdenum0,, 7

20

Vanadium 0.03-0.07

Aluminum 0.02-0.07

Nitrogen0,005-0,012

Phosphorus 0.008-0.015 Mouse KOOOOZO OOZ Tin0.001-0.005 Calcium 0.005-0.15 Iron Others The total content of nickel and manganese is associated with the phosphorus concentration by the following ratio; (Ni + Mn) P 0.037 weightL. Steel may contain impurities, weight: HromDo 0.2 CoDo 0.2 CeraDo 0.02 The specified limits for the content of arsenic and tin at the upper limit of phosphorus concentration, not exceeding 0.015 wt.%, Make it possible to increase the steel resistance to embrittlement during long exposure at elevated temperatures due to a decrease in the non-uniformity of the distribution of elements that reduce the surface energy of the steel developing under these conditions and, at the same time, smelt steel on ordinary charge materials In order to increase the concentration of nickel and manganese steel within the proposed composition did not increase embrittlement due to intergranular phosphorus segregation and long thermal exposures; the total content of nickel and manganese should be related to the phosphorus concentration ratio (Ni + ffa) - Р 0.037 weightD. This ratio determines the permissible concentrations of nickel and manganese depending on the steel purity attained in these technological conditions for phosphorus or, conversely, adjusts the upper limit of the phosphorus content in steel depending on the required for and mechanical properties of nickel and manganese concentrations. The proposed steel additionally contains calcium in the amount of 0.0050, 15 wt.%, Which reduces the embrittlement of the steel during thermal aging due to the reduction of the adverse effect on embrittlement directed due to binding to nonmetallic inclusions of sulfur in the steel. The chemical composition of the proposed steel, (wt.) Three heats are given in table. 1. The mechanical properties of the proposed and known steels after optimal heat treatment are given in table. 2

olo

Claims (2)

1. Steel containing carbon, silicon, manganese, nickel, molybdenum, vanadium, aluminum, nitrogen, phosphorus and iron, characterized in that, in order to reduce the tendency to twist in the process of corrosion resistance (And 350-45p The supplement contains mouse, tin, and calcium in the following ratio of components, wt%: Carbon 0.08-0.1 Silicon0.10-0.37 Manganese 0.6-1, Nickel, 1.7-2.7 Molybdenum0,, 7 Vanadium 0.03-0.07 0.02-0.07 0.005-0.012 0.008-0.013 0.003-0.00 0.001-0.005 0.005-0.150 Else 2. Steel according to Claim 1, which means that the total content of nickel and manganese is related to the phosphorus content by the following ratio: (Ni + Mn) P 0.037 weight. Sources of information taken into account in the examination 1. USSR author's certificate N-, cl. C 22 C 38/12, 1978.