SU933787A1 - Steel - Google Patents

Abstract

STEEL containing carbon, silicon, manganese, chromium, copper, nickel, molybdenum, aluminum, vanadium and iron, characterized in that in order to increase the resistance to layered damage, weldability, resistance to corrosion-mechanical damage, it additionally contains Calcium in the following ratio of components, mas%: 0.08-0.13 Carbon 0.20-0.40 Silicon 0.45-0.75 Manganese 1.05-1.30 Chrome 0.20-0.65 Copper 1 , 05-2.20 Nickel 0.10-0.18 Molybdenum 0.01-0.06 Aluminum 0.01-0.03 Vanadium 0.005-0.050 i Calcium Rest Iron (L

Description

with her with

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1 The invention relates to metal, more specifically to low-carbon structural steel, which is used for the manufacture of ship hulls and structures for marine technical installations, which are subject to high requirements: they must combine a high level of mechanical properties with satisfactory weldability, corrosion resistance and relatively low cost. Known steel containing May 0.3 Carbon 0.08 - 0.8 Silicon 0.5 - 2.0 Manganese Nickel Phosphorus Aluminum 0.005 - 0.0 Calcium iO, 04 Niobium 0.1 Vanadium, 15 Molybdenum Iron Else Reduced steel has insufficient strength about The closest to the described technical essence and achievable result is steel containing, in wt.%: Carbon 0.11-0.15 Silicon 0.2 - 0.4 Manganese O, 8 - 1.05 Molybdenum 0.55 - 0.65 Copper0.6 - 0.8 Tungsten0.15 - 0.40 Vanadium 0.02 - 0.05 №1kel1.4 - 2.0 Chromium 0.75 - 0.95 Aluminum 0.02 - 0.05 Cerium 0, 01 - 0.03 IronErestal Known steel after quenching and HIGH tempering both Sinks following mechanical properties: 5-50 55-1 Thickness of sheet, mm Temporary resistance, kgf / mm Yield strength, kgf / mm Relative narrowing,% Relative elongation,% Impact operation sample with sharp notch along the rolled stock, kgSM at -60 ° C This steel is well welded, has a satisfactory toughness and nifiacTH4HocTbo. However, the welding of known steel in thicknesses up to 100 mm (with the indicated composition of the components in order to avoid cracking) requires a high preheating (400 ° C), which complicates the cost -. em technology manufacturing structures. The problem can be solved by the use of austenitic welding materials, which is economically disadvantageous. The content of sulfur and phosphorus in the known steel is not specified even with the content of sulfur and phosphorus (up to 0.03% of each} cracks and laminated fractures can occur in welded joints, and the steel itself is subject to temper embrittlement. The aim of the invention is to increase the resistance to layered fracture m, weldability and resistance against corrosion-mechanical damage., The goal is achieved by the fact that steel containing carbon, silicon, manganese, chromium, copper, nickel, molybdenum, aluminum, vanadium and iron additionally contains calcium in the following ratio of components, wt.%: Carbon 0.08 - 0.13 Silicon 0.20 - 0.40 Manganese 0.45 - 0.75 1.05 - 1.30 0.20 - 0.65 Nickel 1 , 05 - 2.20 Molybdenum 0.10 - 0.18 Aluminum 0.01 - 0.06 Vanadium 0.01 - 0.03 Calcium 0.005 - 0.050 Iron Rest The total content of copper and nickel is 1.70 - 2.40 %; Steel may contain as impurities,% by mass: Phosphorus 0.005 - 0.015 Sulfur, 0.003 - 0.010 By reducing the carbon and manganese content, the weldability of the steel is improved and welding can be achieved either without heating or with a slight heating in the sheets

3 933787,

up to 100 mm thick, low-alloyed. This is confirmed by the calculation of forts by welding materials without the threat of the International Institute of Welding of the occurrence of cold weather. ki

Si Mp Cr-Ni No V Sy t N with 30 20 20 60 25 That 20 600 60

where Pg is the parameter of crack formation; t - sheet thickness, mm (takes 100); H - content of hydrogen, cm / 100

g (takes 1.0) in For well-known steel of R. with the content of components at the upper and lower levels is 0.470 - 0.571, and for the offered one - 0.387 - 0.500.

Using the cracking parameter, using the formula T Pg 1440–392, we determine the required preheating temperature, which is 280–430 ° C for known steel and 165–300 ° C for the proposed steel.

The chemical composition of steel, wt.%, Is given in tal.1.

T a b l and c a I

The amount of fiber in the fracture when in all cases 400%.

The relative constriction on discontinuous specimens cut in the thickness direction of the sheet (the z-direction) is a characteristic characteristic of the resistance of the steel to a laminated fracture. According to foreign data, the relative narrowing in zet59, 7-60,670,4-72,024,2-23,6

61.2-60.373.6-70.922.8-23.7

56.2-59.171.7-74.023.8-24.8

55-5067-6323-24

40 54-52 65-63 24-23

5052-5264-6354-24

7052-5 G65-6426-28

10051-5265-6423-22

Izvestia58, 3-60, 68.1-70.3 11.4-17.7 per 00 square with a sharp notch (type P according to GOST 9454-78).

6

933787 Continuation of table 1

direction more than 30% of welded joints, non of steel are guaranteed against laminated fractures.

Ingots obtained from smelting 5 roll sheets with a thickness of 30–100 mm on a full dimension,

Table 2 shows the mechanical properties obtained on these sheets after quenching and tempering,

Tables B2

66.3-65.8 65.4-66.8 68.7-68.7 63-68.

64-63 70-70

64-63 69-64

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Table 3 gives an assessment of the weldability of steel.

Table 3. Table 4 gives an estimate of the resistance to a laminated tear on window-type samples (welded card 25150-150) ,. Table 4 50

8 Continued table. 4 20 3U 35 As can be seen from the above data, the described steel has a resistance to brittle fracture at lower temperatures is higher than known, the hardenability of hammered steel, which for all shipbuilding steels is characterized by the presence of a fibrous component in the fracture, after testing at 20 ° C It is provided in all thicknesses and at all proportions of the component pitches. For evaluating the resistance of steel to corrosion and mechanical destruction, tests are carried out on proposed and known steels. Samples are Plates 5-50-100 in size are used. In the center of the plate, along the longitudinal axis on one side, a low-alloyed 48H-II welding electrode with a diameter of 5 mm is applied in a single pass with a 4 mm high roller and a length of 70 80 mm, which simulates the welding cycle . To simulate the welding conditions of a 70 mm thick plate, a copper water-cooled template is used. Studies of the microstructures of the heat-affected zone obtained by this method on plates and on natural sheets show their identity. After deposition of the cladding, the samples are exposed to a corrosive environment by an accelerated method (tested in a boiling solution of 50% NH4N05 and at a boiling point of 108 ° C),. , - The corrosion resistance characteristic is taken up to the time before the appearance of cracks, which originate in the heat affected zone.

9933787

Table 5 presents the results obtained.

4900 4200 4560 4750 3940 4420

3780 It follows from the table that the proposed steel and its welded joints have a higher resistance to corrosion-mechanical damage than known.

ten

Table 5

2630

3260 Manual welding with low-alloyed 48H-11 electrodes is performed with a heat input of 42 kJ. The diffusion hydrogen content in the weld metal is 2.3 g.

Claims (1)

STEEL containing carbon, silicon, manganese, chromium, copper, nickel, molybdenum, aluminum, vanadium and iron, characterized in that, in order to increase resistance to layered fractures, weldability, and resistance to corrosion and mechanical damage, it additionally contains calcium at the following ratio of components. wt.%: Carbon 0.08-0.13 Silicon 0.20-0.40 Manganese 0.45-0.75 Chromium 1.05-1.30 Copper 0.20-0.65 Nickel 1.05-2.20 Molybdenum 0.10-0.18 Aluminum 0.01-0.06 Vanadium 0.01-0.03 Calcium 0.005-0.050 S Iron Rest ω s ON THE ON THE W ςο with co <1 00