CN1077673A - Titania-calcium type simple steel electrode coating - Google Patents

Abstract

A kind of titania-calcium type simple steel electrode coating based on reduced ilmenite, is dosed rutile, titanium dioxide, mid-carbon fe-mn, white clay, marble, sepiolite, feldspar, mica, starch and wood powder.This coating each material in welding process electric arc can form ion, electronic form to greatest extent; Produce the hot slag of low viscosity in the high-temperature region; The utmost point in the short time metal be exceedingly fast the fusing and the purification metal function is played in crystallization again, so the welding arc that the present invention can obtain, hot slag and Welding Metallurgy.Make deposited metal plasticity, toughness and hot-cracking resistance good, improve welding quality, enlarge it in the welding engineering range of application.

Description

Titania-calcium type simple steel electrode coating

The present invention relates to a kind of titania-calcium type simple steel electrode coating, particularly a kind of is the titania-calcium type simple steel electrode coating of main component with reduction titanium calcium iron ore.

The titanium-calcium type coating carbon steel welding electrode just has been widely used in the welding of structural steel from the beginning of the sixties.Just reach more than hundreds of families and the producer that produces this welding rod is only domestic, its prescription is also different.But more employing is to contain TiO ₂98% rutile is the prescription of Main Ingredients and Appearance, and its composition and proportioning are (calculating by weight percentage): rutile 10～30%, titanium dioxide 10～20%, ilmenite 8～16%, mid-carbon fe-mn 12～15%, feldspar 6～11%, marble 4～16%, cloud powder 6～8%, white clay 8～15%, wood powder 1～2%, cellulose 1～2%.

Since costing an arm and a leg of rutile, feasible carbon steel covered electrode cost height based on rutile.In addition, though its most welding rods are tested the mechanical performance standard that meets national regulation in laboratory, but because the defective that producer's selection and proportioning itself exist, have following shortcoming and defect in the application of actual engineering: molten of electric arc is thin inadequately, the soft property of electric arc, poor stability, the operator perception is good inadequately; The welding current scope is narrower, and adaptability thin to welding, thick steel is relatively poor; The physical property of liquid slag is poor, to the adaptability of all-position welding and all good inadequately to the welding of the weld seam of different geometries; Heat crack resistance is poor, the plasticity of deposited metal, toughness are stable inadequately; Restarting is poor; The coating moisture resistivity is poor; Deoxidier in the coating-mid-carbon fe-mn consumption is many.

For overcoming the deficiencies in the prior art, the purpose of this invention is to provide a kind of function admirable, titania-calcium type simple steel electrode coating prescription that cost is low, so that improve the performance of welding rod and reduce its cost, and enlarge its range of application in welding engineering.

For this reason, titania-calcium type simple steel electrode coating prescription of the present invention is:

Reduced ilmenite 45～50%;

Rutile 6～9%

Titanium dioxide 1～3%

Mid-carbon fe-mn 6～8%

White clay 5～8%

Marble 12～14%

Sepiolite 2～4%

Feldspar 7～9%

Mica 6～8%

Starch 1～2%

Wood powder 1～2

Titanium-calcium type coating of the present invention mainly is to do electric arc and weld pool protection with slag, purifies this titanium-calcium type coating of deposited metal with slag and belongs to TiO ₂-CaO-SiO ₂The ternary slag system promptly mainly constitutes slag with these three kinds of compositions.Now set forth the main effect of these three kinds of compositions respectively.

TiO ₂: be good acid slag former, its effect: stable arc; Reduce the viscosity of slag, be beneficial to metallurgical reaction at hot stage; Make the hurried rising of viscosity coefficient of dross with the temperature reduction, the also corresponding increase of surface tension is beneficial to weld ripples appearance.Its shortcoming: increase the SiO in the corresponding non-metallic inclusion that makes weld metal with consumption ₂Amount increases, and the plasticity of weld metal and toughness are reduced.

CaO: use CaO and MgO simultaneously in this prescription, both character is basic identical, is good alkaline slag former.With TiO ₂Or SiO ₂Be combined to salt; Balance slag acid-base value reduces the non-metallic inclusion content of weld metal and reduces SiO ₂Composition is to improve the plasticity and the toughness of weld metal.How its side effect consumption can change the slag thermophysical property and worsen welding technological properties.

SiO: be acid slag former, SiO ₂Be combined to salt with CaO or MgO, form little, the cellular frivolous filled slag of proportion.Its side effect is how consumption can cause slag acidity height, and makes the viscosity height in cinder high-temperature stage, and viscosity increases again slowly with the temperature reduction.The variation of this physical property just with TiO ₂On the contrary, be unfavorable for metallurgical reaction.

TiO ₂In the present invention's prescription, select reduced ilmenite, rutile, three kinds of raw materials of titanium dioxide for use.Though these three kinds of raw materials all contain TiO ₂, but contain other composition difference, and the physical property difference, C in the reduced ilmenite and FeO are the useful compositions that needs in the electric arc, but should be controlled at certain limit.C:C+ ¹/ ₂O ₂→ CO plays deoxidation, contains too high can the increasing of C and splashes.FeO: need certain amount to fill the atmosphere of oxygen in the electric arc, the acidity of balance slag.This be because, under the high arc temperature effect, because of containing TiO ₂SiO in the high coating ₂In electric arc, weld pool, be easy to generate following displacement reaction:

Because the effect of FeO may produce following several reaction again, forms salt at last:

Reduce the viscosity of slag in the melting welding, utilize in the weld metal all gases outwards to overflow.

Contain 36～38% Fe in the reduced ilmenite, increase the deposition rate of deposited metal, improve welding efficiency, play adding iron powder equivalent effect in the prescription.

The effect of rutile and titanium dioxide is for TiO in the balance coating ₂Content.Another effect of titanium dioxide is plasticity and the whiteness that increases coating.

The effect of white clay, feldspar, mica, sepiolite is that a side is as SiO in the balance coating ₂Composition, extrusion performance and the coating intensity in order to increase medicinal powder in addition.Extrusion is called medicinal powder before becoming coating, and medicinal powder should possess certain plasticity, elasticity, sliding property and sliding could become welding rod by extrusion.White clay, sepiolite have bigger plasticity, and mica has bigger sliding property and elasticity, and feldspar contains the K of volume ₂O, but stable arc.

Mid-carbon fe-mn is a deoxidier.

Starch also is deoxidier, and its fusing point is low, plays the precedent desoxydation effect, produces CO and CO ₂, can play the gas shield arcing.

Wood powder except that play with starch same deoxidation and gas shield arcing, it also has very big elasticity, can increase the elasticity of medicinal powder.

Its prescription advantage is as follows:

1. welding arc has high degree of ionization, and electric arc is soft, and flameholding is easily answered hand in welding operation, comfort is arranged, the welding quality that can obtain, and also welding efficiency improves nearly 10%

2. obtain in welding process that viscosity is low, body is light, the molten slag of active, filled, coagulated mass, thermophysical property that surface tension is moderate.This molten slag is beneficial to downhand welding, vertical position welding, horizontal position welding, overhead welding operation, is beneficial to wide weld ripples, narrow weld ripples, weld ripples elongates, the weld ripples heap is thick operation; Be beneficial to and make annular solder, generally make annular welds and can adjust electric current.

3. in electric arc and weld pool process, obtain good metallurgical reaction, make H in the deposited metal ₂, N ₂, O ₂Greatly reduce with non-metallic inclusion content, thus plasticity, impact flexibility and the heat crack resistance of raising weld metal.

4. acquisition has slight electric conductivity by the coating sleeve of electrode end first meltization, makes restarting easy.

5. chemical coating of welding electrode has certain moisture resistivity, is beneficial at the humid site weld job, and welding quality is unaffected, and welding rod is deposited the weld metal that welded again in 24 hours and done x-ray inspection under the condition of 30 ℃ of temperature, 80 ° of relative humidity, meet the II grade standard.

6. the granularity proportioning effect of the various raw materials of coating and contain fibrous material and make coating that resistance to bend(ing) be arranged, welding rod is flexible more than 90 °, can adapt to the welding operation of narrow welding position.

7. coating has the volume iron powder, and the receipts of deposited metal are applied rate and improved 8% than general similar welding rod.

8. oxidation material and reducing substances are taked multiple equilibrium in the coating, and conventional deoxidier-mid-carbon fe-mn amount ratio titania-calcium type simple steel electrode coating consumption of the prior art of coating is lacked about 20%, and welding rod cost per ton can be saved about 35 yuan.

Preferred embodiment of the present invention following (by weight percentage)

Reduced ilmenite 45%

Rutile 6%

Titanium dioxide 2%

Mid-carbon fe-mn 7%

White clay 6%

Marble 13%

Sepiolite 4%

Feldspar 8%

Mica 6%

Starch 1%

Wood powder 2%

Its prescription raw material main chemical compositions (percentage by weight) and granularity require:

Reduced ilmenite:

TiO ₂〉=55% granularity :-40 orders 100%

C≤0.25%-200 order≤10%

FeO≤7% loose specific weight :≤1.8g/cm ³

Fe 〉=36% magnetic separation is inhaled surplus :≤1.3g/cm ³

S≤0.05% outward appearance: cellular grey black coloured particles

P≤0.05%

Rutile:

TiO ₂〉=87% granularity :-40 orders 100%

C≤0.06%-140 order≤10%

Fe≤6% loose specific weight :≤1.8g/cm ³

S≤0.04% outward appearance: brown particle shape

P≤0.04%

Titanium dioxide:

TiO ₂〉=98% granularity :-140 orders 100%

S≤0.05%-300 order 〉=90%

P≤0.05% loose specific weight :≤0.5%g/cm ³

Mid-carbon fe-mn:

Mn 〉=75% granularity :+50 orders 0%

C≤1.5%+60 order 5%

Si≤2.5%-200 order≤35%

P≤0.3%

S≤0.02%

White clay:

SiO ₂60～73% granularities :-200 orders 100%

Al ₂O ₃15～25%-300 orders 〉=95%

S≤0.05% loose specific weight :≤0.6g/cm ³

P≤0.05% outward appearance: white powder powdery

Marble:

CaCO ₂〉=95% granularity+50 orders 0

S 〉=0.03%+60 order≤5%

P≤0.03-200 order≤40%

Loose specific weight: 〉=1

Outward appearance: white powdery

Sepiolite:

SiO ₂60% granularity :-200 orders 100%

MgO 〉=25%-300 order 〉=95%

S≤0.05% loose specific weight :≤0.6g/cm ³

P≤0.05% outward appearance: white powder powdery

Feldspar:

SiO ₂63～73% granularities :-60 orders 100%

Al ₂O ₃15～22%-200 orders≤50%

K ₂O+Na ₂O 〉=12% loose specific weight: 〉=1.1g/cm ³

S≤0.05% outward appearance: white powder or white

P≤0.05%

Mica:

SiO ₂44～52% granularities+24 orders 0%

Al ₂O ₃20～33%+40 orders≤1%

-80 orders≤40%

Loose specific weight :≤0.4

Outward appearance: green translucent flat crystal

K ₂O+Na ₂O≥7%

S≤0.05%

P≤0.05%

Starch:

Granularity :-60 orders 100%

Loose specific weight :≤0.5g/cm ³

Outward appearance: white, powdery

Wood powder:

Granularity :-60 orders 100%

Loose specific weight :≤0.3g/cm ³

With the welding rod that this prescription is made, weldering skin specification 4.0mm, welding rod diameter 6.40mm～6.60mm.

Carry out soldering test with above-mentioned welding rod, weld metal is through 50 tests, and its test data is as follows:

σb MPa	δs%	AKVJ -20℃
			440～490	25～34	70～115

Annotate: coupon is without the result of the test of dehydrogenation.

σ _b: fracture strength: δ _s: percentage elongation; VJ: impact value

Through evidence, the lime-titania type welding rod that scribbles this coating meets Chinese GB II 4303; 41 grades of the ZC of Chinese vessel office III, the LR3 of British Corporation level, U.S. ship's classification ABS3 grade standard (3 grades is the acidic electrode superlative degree).

Claims (1)

1, a kind of titania-calcium type simple steel electrode coating, its composition comprises rutile, ilmenite, mid-carbon fe-mn, feldspar, marble, mica, white clay, wood powder and starch, the invention is characterized in the reduced ilmenite to be Main Ingredients and Appearance, and dose titanium dioxide, sepiolite, starch, its concrete composition and proportioning following (calculating by weight percentage):

Reduced ilmenite 45～50%;

Rutile 6～9%

Titanium dioxide 1～3%

Mid-carbon fe-mn 6～8%

White clay 5～8%

Marble 12～14%

Sepiolite 2～4%

Feldspar 7～9%

Mica 6～8%

Starch 1～2%

Wood powder 1～2%