CN1027548C - Wear-corrosion resistant austenitic cast iron and manufacturing technique - Google Patents

Abstract

The present invention relates to a wear-resisting corrosion-resisting austenite cast iron and its production technology, and is an iron-base alloy using Cr, Ni, Cu, Mo, C and Si as main alloy elements. It can replace monel alloy and 303 austenite cast iron, and can be used as metal material for resisting salt slurry corrosion, and its durability used on salt slurry pump is above 20 times of that of 18-8 stainless steel, and above 65 times of that of tungsten-manganese wear-resisting white cast iron, and is superior to monel alloy, and its production cost is far lower than monel alloy, and it has very obvious economic benefit in salt production.

Description

Anti-abrasive and anti-corrosive austenic cast iron and its producing technology

Resistance to wear resistant alloy and manufacturing technology thereof of the present invention belongs to alloy material and manufacturing process.

Alloy of the present invention, it is a kind of novel anti erosion corrosion alloy, in industrial production, salt slurry is very serious to the erosion corrosion of hardware such as pump, valve, pipeline etc., the anti-salt slurry of the equipment that materials such as domestic use plain cast iron, tungsten manganese 2 wear-resistant white cast, stainless steel are manufactured corrosive power is poor, titanium alloy on probation, copper alloy are not obtained the anti-salt slurry of ideal corrosive effect yet, because when containing solid particulate in the corrosive liquid body medium, solids are understood the corrosion failure of 1,100 times acceleration equipment to the souring of hardware.The external method that solves salt slurry erosion corrosion material all is to adopt to have the very valuable alloy of high heating power stability in salt solution, all adopt as some industrially-advanced countries in the world to contain that Ni is about 70%, the Monel metal of Cu about 30% is made brine pump, its tensile strength is greater than 450N/mm ², yield strength is greater than 210N/mm ², unit elongation 32.5%, hardness＞HB120.This corronel has excellent solidity to corrosion in seawater and salt solution, and shock resistance might as well, but Monel metal costs an arm and a leg, production technique is poor, the melting and casting difficulty is big, should not apply at present in China, and external many major companies such as International nickel Co. Ltd. Inco. Ltd., West Germany plum rope chemical technology company etc. adopt comparatively cheap austenitic iron, 30%Ni according to reports, 303 austenitic irons of 3%Cr have the ability of good anti-salt slurry erosion.Still there is not systematic study about the mechanism of corrosion of metallic substance in the salt slurry both at home and abroad at present.The present invention is to be the ferrous alloy of main alloy element by having created a kind of to current material in the mechanism of corrosion analysis in the salt slurry with Cr, Ni, Cu, Mo, C, Si, finds the prior art identical or close with the present invention by retrieval.

The objective of the invention is to replace Monel metal and austenitic iron with above-mentioned ferrous alloy, develop the new special cast iron salt tolerant slurry corrosion material that is fit to China's needs, cost is low, and the life-span is long, has solved the key issue of anti-salt slurry corrosion with material.

Alloy of the present invention is not to adopt the anti-corrosion this traditional selection method of thermodynamic stability of depending merely on self, even dispersion is distributed with an amount of bulk on the metallic matrix of excellent preferably passivation type of solidity to corrosion and high thermal stability but make, short strip shape high rigidity carbide, make the matrix between carbide not be subjected to the direct impact of solids, thereby improved the corrosion resistance of alloy.

This alloy is that its composition of ferrous alloy is:

C0.5～3.5%

Cr21～35%

Si0.5～4.2%

Ni4.05～12%

Mn0.5～1.5%

Cu1～6%

Mo0.5～3%

Surplus is Fe.

The content of alloying constituent Ni of the present invention, Cu directly influences this thermodynamics of alloys stability, and therefore, Ni, the Cu content in alloy substrate must meet following formula:

Ni%+Cu%≥15%

Can be with reference to following formula in order to make alloy obtain in the salt slurry that only hardness: HRC26～34 are becoming in the component selections:

6.3(C%+1/3Si%)+the required hardness of 15.6=HRC

In order to improve the impelling strength of alloy, except that its chemical ingredients of correct selection, also will be with the alterant of the present invention preparation, to the alloy processing of going bad.

The alterant composition is:

Mg5～8%;

V8～12%;

Ti4～7%;

B1～3%;

Sn0.2～1%;

Mo0.2～1%。

Adding method: pour method or plunging.

Add-on is 0.3～1.0% of a molten metal weight.

Advantage of the present invention is:

Anti-salt slurry corrosive power is strong, it uses on brine pump, durability is 18～8 stainless more than 20 times, be more than 65 times of tungsten manganese wear-resistant white iron, and being better than covering is alloy, production cost is far below Monel metal, inactivating performance and the pitting corrosion resistant performance of this alloy in salt solution also is better than 18～8 stainless steels, its anti-cavitation erosion ability is 18～8 stainless 2 times, and its cost is close with 18～8 stainless steels, only calculates the brine pump that adopts alloy of the present invention with regard to salt industry, valve, pipeline and consumable accessory, the user can save this kind equipment, spare part expense 90%, save maintenance man-hours and take 50%, remarkable benefit.

Embodiment:

This alloy adopts intermediate frequency, main frequency furnace or electric arc furnace melting batch to select material, and composition will be by table 1 requirement, and impurity contents such as P, S are not too high.Furnace charge shove charge order is the pig iron-steel scrap-foundry returns-Ni-Cu-Mo iron-Cr iron-ferrosilicon and ferromanganese.Molten iron dissolves and is warmed up to 1590 ℃ and comes out of the stove with the 0.05%Al deoxidation, and with pouring method or bell jar plunging adding alterant (composition as mentioned above), add-on is 0.6% of a weight of molten iron in the bag.

Carry out skimming for twice after rotten the processing, the back covers hot metal ladle with lagging material, and foundry goods is made in casting.

Select composition for use:

Table 1

Composition example one example two

C 2.70 0.71

Si 1.51 0.61

Mn 0.81 1.43

Cr 26.61 28.50

Ni 11.32 7.56

Cu 5.35 4.12

Mo 0.63 1.52

P 0.05 0.035

S 0.02 0.019

Tissue: austenite adds carbide (example one) or austenite and adds a little ferrite and add carbide (example two); Hardness: HRC26; Impact value; 5.8N/cm before rotten ²(example one), 10.5N/cm ²(example two); Rotten back 10.2N/cm ²(example one); 13.4N/cm ²(example two), tensile strength 560N/cm ², unit elongation 4%.

Claims (2)

1, a kind of corrosion austenitic iron that resistance to wears is characterized in that: agglomerate, short strip shape carbide even dispersion are distributed on the matrix of excellent passivation and higher thermal stability, and its composition is:

C0.5～3.5%

Cr21～35%

Si0.5～4.2%

Ni4.05～12%

Mn0.5～1.5%

Cu1～6%

Mo0.5～3%

Surplus is Fe.

2, a kind of corrosion austenitic iron metamorphism treatment method that resistance to wears is characterized in that the processing of going bad of alterant with the following compositions preparation:

The composition of alterant: Mg5～8%, V8～12%, Ti4～7%, B1～3%, Sn0.2～1%, Mo0.2～1%, add-on is 0.3～1.0% of a metal liquid measure, the adding method is for pouring method or plunging.