CN104745920A - Method for manufacturing ship rudder arm - Google Patents

Abstract

The invention discloses a method for manufacturing a ship rudder arm. The method is characterized in that a melting process is developed, wherein the melting process comprises ingredient selection, smelting temperature control, oxygen blowing, argon blowing parameter control and the like, and control over the chemical element content, especially aluminum content and nitrogen content, meets the requirement; an optimal casting process is compiled, wherein the casting process comprises riser and sprue design and molding material selection, generation of cracks and shrinkage porosity is completely eradicated, nondestructive testing of a casting is achieved, and the size precision requirement of the casting is met; and a specific heat treatment process is compiled, wherein the heat treatment process comprises selection of temperature and time for temperature rising, heat preservation and temperature dropping, and especially applying of a cooling method, the problem that the mechanical performance of the casting is insufficient is solved, and particularly, the low-temperature impact performance requirement is met.

Description

The manufacture method of ship rudder horn

 

Technical field

The invention belongs to casting technology field, be specifically related to a kind of manufacture method of ship rudder horn.

 

Background technology

The manufacturing process of ship rudder horn at least comprises the processes such as melting, reduction, thermal treatment, in current ship rudder horn pouring technology, the casting finished products hardness made is inadequate, and not only casting process is more, affect production capacity, technical quality parameter does not reach the MAT'L specification requirement of external surveying society simultaneously.

 

Summary of the invention

In order to overcome the above-mentioned technical problem that prior art field exists, the object of the invention is to, provide a kind of manufacture method of ship rudder horn, directly can cast out finished product ship rudder horn foundry goods, and the precision of foundry goods is high, processing technology thereof is simple.

The manufacture method of ship rudder horn provided by the invention, comprises the following steps:

(1) fusion stage: by returns 30-45%, steel cuttings 15-25%, pig iron 10-15%, lime 1-2%, surplus is steel scrap, and drop into energising fusing in electric furnace, oxygen blast is simultaneously fluxed, oxygen lance diameter 1/2-3/4 ', pressure 5-10 kilograms per centimeter 2, after molten steel is melting down, sampling analysis carbon, phosphorus;

(2) oxidation stage: add iron ore 1-2%, lime 1-2% in melting down molten steel, oxygen blast simultaneously, oxygen lance diameter 1/4-1 ', pressure 6-8 kilograms per centimeter 2, time controling is at 10-15 minute, and make carbon content reach 0.05-0.1% after carbon drop dephosphorization terminates, phosphorus is lower than 0.035%, liquid steel temperature reaches 1590-1640 DEG C, removes oxidation sludge;

(3) reduction phase: add lime 8-12 kg/tonne molten steel in molten steel, fluorite 1-2 kg/tonne molten steel, carbon dust 1-1.5 kg/tonne molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.3-0.6% in molten steel, Mn to 1.2-1.6%, and add reductor aluminium block 0.1-0.2% and carry out pre-deoxidation, make temperature reach tapping temperature 1570-1600 DEG C;

(4) refining stage: the molten steel in electric furnace is forwarded in refining furnace, then add lime 2-5 kg/tonne molten steel, fluorite 0.5-1 kg/tonne molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.25-0.60%, Mn to 1.4-1.6% in molten steel; Furnace bottom passes into the argon gas of 5-8 kilograms per centimeter 2 until refining terminates with the pipe of diameter 1/2-3/4 ' simultaneously;

(5) tap: add reductor aluminium block 0.05-0.2% before tapping and carry out final deoxygenation, sampling detects chemical composition and reaches the tapping of standard analysis scope, calmer 5 minutes, temperature running castings when reaching 1560-1590 DEG C;

(6) moulding: adopt cored-up mould, crust loam core quartz sand, inner chamber loam core and top box loam core use magnesium carbon-lime sand, and enter kiln and dry 8-12 hour at 250-350 DEG C, remove the moisture in loam core, reduce loam core time gas forming amount, fill out at fillet place of coremaking time institute and put chromite sand and dark contoured chill; Carefully size is checked after core setting; Rising head clay core part wooden model is made, and rest part joins insulating riser sleeve, and cast chooses many ladle combined castings, slide gate nozzle diameter 60-80mm, requires within 6-10 minute, complete, when molten steel in rising head rises 2/3 high time point dead head spread heat preserving agent after cast;

(7) thermal treatment process: the work in-process after casting are cooled to less than 350 DEG C, the residual sand of the interior outside of remove feeders, cast gate, foundry goods after the demoulding, be placed in again in heat treatment furnace, slowly be warming up to 600-700 DEG C, temperature rise rate is 60-70 DEG C/h, be incubated soaking when 600-700 DEG C and cross the split plot that becomes different mutually in 3-5 hour, continue afterwards to be warming up to 850-910 DEG C, insulation 16-20 hour.

The manufacture method of ship rudder horn provided by the invention, its beneficial effect is, overcomes operation in the prior art course of processing more, the problem that workload is large, improves production efficiency; Solve the problem of foundry goods mechanical property deficiency, especially low temperature impact properties requirement, utilization rate of raw materials is high, reduces production cost; The final dimension cast out is accurate, without the need to mechanical workout, effectively ensure that casting quality.

 

Embodiment

Below in conjunction with an embodiment, the manufacture method of ship rudder horn provided by the invention is described in detail.

Embodiment

The manufacture method of the ship rudder horn of the present embodiment, comprises the following steps:

(1) fusion stage: by returns 40%, steel cuttings 30%, the pig iron 10%, lime 1%, surplus is steel scrap, and drop into energising fusing in electric furnace, oxygen blast is simultaneously fluxed, oxygen lance diameter 1/2 ', pressure 8 kilograms per centimeter 2, after molten steel is melting down, sampling analysis carbon, phosphorus;

(2) oxidation stage: add iron ore 2%, lime 1% in melting down molten steel, oxygen blast simultaneously, oxygen lance diameter 1/4, pressure 7 kilograms per centimeter 2, time controling was at 13 minutes, and make carbon content reach 0.08% after carbon drop dephosphorization terminates, phosphorus is lower than 0.035%, liquid steel temperature reaches 1600 DEG C, removes oxidation sludge;

(3) reduction phase: add lime 10 kgs/tonne of molten steel in molten steel, fluorite 1.5 kgs/tonne of molten steel, carbon dust 1.3 kgs/tonne of molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.5% in molten steel, Mn to 1.4%, and add reductor aluminium block 0.15% and carry out pre-deoxidation, make temperature reach tapping temperature 1590 DEG C;

(4) refining stage: the molten steel in electric furnace is forwarded in refining furnace, then add lime 4 kgs/tonne of molten steel, fluorite 0.8 kg/tonne of molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.20%, Mn to 1.5% in molten steel; Furnace bottom passes into the argon gas of 7 kilograms per centimeter 2 until refining terminates with the pipe of diameter 3/4 ' simultaneously;

(5) tap: add reductor aluminium block 0.1% before tapping and carry out final deoxygenation, sampling detects chemical composition and reaches the tapping of standard analysis scope, calmer 5 minutes, temperature running castings when reaching 1580 DEG C;

(6) moulding: adopt cored-up mould, crust loam core quartz sand, inner chamber loam core and top box loam core use magnesium carbon-lime sand, and enter kiln to dry 10 hours at 300 DEG C, remove the moisture in loam core, reduce loam core time gas forming amount, fill out at fillet place of coremaking time institute and put chromite sand and dark contoured chill; Carefully size is checked after core setting; Rising head clay core part wooden model is made, and rest part joins insulating riser sleeve, and cast chooses many ladle combined castings, slide gate nozzle diameter 70mm, requires within 7 minutes, complete, when molten steel in rising head rises 2/3 high time point dead head spread heat preserving agent after cast;

(7) thermal treatment process: the work in-process after casting are cooled to less than 350 DEG C, the residual sand of the interior outside of remove feeders, cast gate, foundry goods after the demoulding, be placed in again in heat treatment furnace, slowly be warming up to 650 DEG C, temperature rise rate is 65 DEG C/h, 660 DEG C time, be incubated soaking cross the split plot that becomes different mutually in 4 hours, continue afterwards to be warming up to 860 DEG C, be incubated 18 hours.

The manufacture method of ship rudder horn, can directly cast out ship rudder horn foundry goods, and without the need to mechanical workout, operation is simple, and the finished product cast size cast out is accurate, effectively ensure that casting quality.

Claims (1)

1. a manufacture method for ship rudder horn, is characterized in that: said method comprising the steps of:

(1) fusion stage: by returns 30-45%, steel cuttings 15-25%, pig iron 10-15%, lime 1-2%, surplus is steel scrap, and drop into energising fusing in electric furnace, oxygen blast is simultaneously fluxed, oxygen lance diameter 1/2-3/4 ', pressure 5-10 kilograms per centimeter 2, after molten steel is melting down, sampling analysis carbon, phosphorus;

(2) oxidation stage: add iron ore 1-2%, lime 1-2% in melting down molten steel, oxygen blast simultaneously, oxygen lance diameter 1/4-1 ', pressure 6-8 kilograms per centimeter 2, time controling is at 10-15 minute, and make carbon content reach 0.05-0.1% after carbon drop dephosphorization terminates, phosphorus is lower than 0.035%, liquid steel temperature reaches 1590-1640 DEG C, removes oxidation sludge;

(3) reduction phase: add lime 8-12 kg/tonne molten steel in molten steel, fluorite 1-2 kg/tonne molten steel, carbon dust 1-1.5 kg/tonne molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.3-0.6% in molten steel, Mn to 1.2-1.6%, and add reductor aluminium block 0.1-0.2% and carry out pre-deoxidation, make temperature reach tapping temperature 1570-1600 DEG C;

(4) refining stage: the molten steel in electric furnace is forwarded in refining furnace, then add lime 2-5 kg/tonne molten steel, fluorite 0.5-1 kg/tonne molten steel, add alloy SiMnFe, MnFe and SiFe and adjust Si to 0.25-0.60%, Mn to 1.4-1.6% in molten steel; Furnace bottom passes into the argon gas of 5-8 kilograms per centimeter 2 until refining terminates with the pipe of diameter 1/2-3/4 ' simultaneously;

(5) tap: add reductor aluminium block 0.05-0.2% before tapping and carry out final deoxygenation, sampling detects chemical composition and reaches the tapping of standard analysis scope, calmer 5 minutes, temperature running castings when reaching 1560-1590 DEG C;

(6) moulding: adopt cored-up mould, crust loam core quartz sand, inner chamber loam core and top box loam core use magnesium carbon-lime sand, and enter kiln and dry 8-12 hour at 250-350 DEG C, remove the moisture in loam core, reduce loam core time gas forming amount, fill out at fillet place of coremaking time institute and put chromite sand and dark contoured chill; Carefully size is checked after core setting; Rising head clay core part wooden model is made, and rest part joins insulating riser sleeve, and cast chooses many ladle combined castings, slide gate nozzle diameter 60-80mm, requires within 6-10 minute, complete, when molten steel in rising head rises 2/3 high time point dead head spread heat preserving agent after cast;

(7) thermal treatment process: the work in-process after casting are cooled to less than 350 DEG C, the residual sand of the interior outside of remove feeders, cast gate, foundry goods after the demoulding, be placed in again in heat treatment furnace, slowly be warming up to 600-700 DEG C, temperature rise rate is 60-70 DEG C/h, be incubated soaking when 600-700 DEG C and cross the split plot that becomes different mutually in 3-5 hour, continue afterwards to be warming up to 850-910 DEG C, insulation 16-20 hour.