CN1172769C - A high cellulose welding rod - Google Patents

Abstract

The present invention relates to a high-cellulose type welding rod which is a novel high-cellulose type welding rod aiming at solving the defects of the existing high-cellulose type welding rods that coating covers become red during welding application, welding seams have pores, and low-temperature impact toughness is low. A coating cover of the present invention has components of microcrystalline glass, starch, bamboo powder, rutile, titanium white powder, magnesite, sepiolite, mica, nickel powder, ferromolybdenum, medium carbon ferromanganese, rare earth ferrosilicon, iron sand and magnesite sand. A proper quantity of microcrystalline fibers, the sepiolite, the rutile, the magnesite sand and the iron sand are used as main slagging agents. Meanwhile, water glass with lower modulus and higher concentration of ratio of K to Na is used as binding agents. The components and the mechanical properties of the present invention accord with international requirements. A low-temperature charpy notch impact value Akv (-30DEG C) reaches 90 J, which is superior to similar famous welding rods at home and abroad. The technological performance of the welding rod of the present invention is good and can meet the requirement of the operation of whole-place downward welding of a tube. Moreover, the present invention has the characteristics that the coating cover of the welding rod of the present invention can not become red during welding application, the welding seams of the present invention have no pore, the low-temperature impact toughness of the present invention is excellent, etc.

Description

A high cellulose welding rod

technical field

The invention relates to a high-cellulose welding rod used for pipeline welding, which belongs to the technical field of welding.

Background technique

In recent years, the high-cellulose type electrodes researched and developed in China are E4310 (should comply with the national standard GB/T5117-1995) and E5510 (should comply with the national standard GB/T5118-1995). Poor operability, red electrode coating, pores in the weld seam and low low-temperature impact toughness, and has not yet formed mass production, so most of them rely on imports to meet domestic needs. Firstly, the cost is high, and secondly, the impact toughness of welding rods of famous foreign brands needs to be further improved.

People such as Zhang Qinghui disclosed the performance index of a kind of E4310 cellulose electrode in " the research of improved E4310 cellulose electrode " (Welding Technology, 2001, (4): 43-44), accord with national standard GB/T5117-1995, but It is suitable for steel with relatively low welding strength. The "Research on E5510-G High Cellulose Electrode" researched by He Shaoqing and others (Welding Technology, 1998, (4): 28-30) complies with the national standard GB/T5117-1995, and the mechanical properties achieved by the deposited metal are, The tensile strength σb is 701 MPa, the yield point σs is 584 MPa, the elongation δ5 is 26%, and the Akv at -30°C is 30, 32, 34, 38, 40 joules, but there are still low-temperature impact toughness defect.

The large amount of cellulose contained in the electrode coating decomposes a large amount of reducing gas during the welding process, and adds carbon and hydrogen to the deposited metal, resulting in greater sensitivity to pores and seriously deteriorating the low temperature of the electrode weld metal. Toughness; a large amount of cellulose substances contained in the coating is also the root cause of the low carbonization point of the electrode and the red coating of the electrode. Electrode slag is an acidic slag with low alkalinity, which is not conducive to the improvement of low temperature toughness.

Contents of the invention

The purpose of the present invention is to provide a high-cellulose-type electrode to overcome the defects of the existing high-cellulose-type electrode, such as poor processability, red coating of the electrode, and pores in the weld seam, while further improving low-temperature impact toughness.

The purpose of the present invention is achieved through the following technical solutions: a high cellulose type electrode, including welding core, coating and adhesive, is characterized in that described coating composition and content (percentage by weight) are respectively:

                                                                                                          

Starch: 1～3%

Bamboo powder: 3～5%

Rutile: 10～12%

Titanium dioxide: 1～3%

                                                                      

Sepiolite: 10～12%

Mica: 2～4%

Iron powder: 5～7%

Nickel powder: 3.5～4.5%

Ferromolybdenum: 1～1.5%

  Medium Carbon Ferromanganese: 6～8%

          Rare earth ferrosilicon: 2-3.5%

Iron Sand: 8～10%

Magnesia: 4-6%.

The content (percentage by weight) of each component of above-mentioned high cellulose electrode coating also can adopt following ratio:

           Microcrystalline Fiber: 30%

Starch: 1%

Bamboo Powder: 4%

Rutile: 12%

Titanium dioxide: 2%

                                                       

Sepiolite: 11%

Mica: 3%

Iron powder: 5%

Nickel powder: 4%

Ferromolybdenum: 1.5%

  Medium Carbon Ferromanganese: 7%

             Rare Earth Ferrosilicon: 2.5%

Iron sand: 8%

Magnesia: 6%.

The adhesive of the high cellulose type welding rod of the present invention adopts water glass with a modulus of 2.8-3.0M, a potassium-sodium ratio of 2:1, and a concentration of 40.5°Be'-43.0°Be'.

The invention adopts the SiO2-TiO2-MgO-FeO slag system, appropriately increases the alkalinity of the slag, can obtain good process performance, better solves the carbonization problem of the electrode and reduces the porosity tendency. Substances containing TiO2, SiO2, MgO, and FeO can significantly improve the anti-redness performance of the electrode within a certain content range. The test shows that microcrystalline fiber, sepiolite, rutile, magnesia, and iron sand are selected as the main components of the coating. The slag-forming agent is used in an appropriate amount, which can better solve the carbonization problem of the electrode and improve the anti-redness performance of the high-cellulose electrode. The test shows that adding strong oxidant iron sand to the coating can balance the oxidation-reduction characteristics of the coating, which greatly improves the anti-porosity ability of the electrode.

Because the present invention selects the water glass with lower modulus and higher concentration of potassium-sodium ratio as the binder, and properly controls its addition amount, the electrode coating performance is good.

After measurement, the chemical composition of the deposited metal of the present invention is: C: 0.082%, Ni: 1.54%, Mo: 0.21%, Mn: 0.56%, Si: 0.13%, S: 0.008%, P: 0.012% and trace rare earth elements . The electrode (TH·J555E) has an average -30°C impact toughness of 90 joules on the deposited metal, which is superior to similar electrodes known at home and abroad. Due to the reasonable slag system, low carbon, nickel, molybdenum and rare earth elements, and low sulfur and phosphorus content, it leads to high toughness.

Detailed ways

Example 1

The welding core material, coating formula and adhesive of high cellulose type electrode (TH J555) are as follows:

1. Solder core: HO8C, HO4E

2. Formula of electrode coating:

Table 1 microcrystalline fiber starch bamboo powder rutile Titanium dioxide Diamond Bitter Soil meerschaum Mica iron powder nickel powder Ferromolybdenum Medium carbon ferromanganese Rare earth ferrosilicon iron sand Magnesia 30 1 4 12 2 3 11 3 5 4 1.5 7 2.5 8 6

3. Adhesive: water glass

The modulus of water glass is 2.8-3.0M, the ratio of potassium to sodium is 2:1, the concentration is 40.5°Be'-43.0°Be', and the addition amount is controlled at 40%.

Example 2

The welding core material, coating formula and adhesive of high cellulose type electrode (TH J555) are as follows:

1. Solder core: HO8C, HO4E

2. Formula of electrode coating:

Table 2 microcrystalline fiber starch bamboo powder rutile Titanium dioxide Diamond Bitter Soil meerschaum Mica iron powder nickel powder Ferromolybdenum carbon ferromanganese Rare earth ferrosilicon iron sand Magnesia 29 2 5 11 1 4 12 2 5 4.5 1 6 3.5 9 5

3. Adhesive: water glass

The modulus of water glass is 2.8-3.0M, the ratio of potassium to sodium is 2:1, the concentration is 40.5°Be'-43.0°Be', and the addition amount is controlled at 45%.

Example 3

The welding core material, coating formula and adhesive of high cellulose type electrode (TH J555) are as follows:

1. Solder core: HO8C, HO4E

2. Formula of electrode coating:

table 3 microcrystalline fiber starch bamboo powder rutile Titanium dioxide Diamond Bitter Soil meerschaum Mica iron powder nickel powder Ferromolybdenum Medium carbon ferromanganese Rare earth ferrosilicon iron sand Magnesia 31 3 3 10 3 2 10 4 5 3.5 1.5 8 2 10 4

3. Adhesive: water glass

The modulus of water glass is 2.8-3.0M, the ratio of potassium to sodium is 2:1, the concentration is 40.5°Be'-43.0°Be', and the addition amount is controlled at 50%.

Embodiment has been carried out following performance test:

(1) mechanical property of deposited metal of the present invention

The various mechanical properties of the deposited metal of the present invention are carried out according to the national standard GB/T5118-1995, and are tested by the Hubei Provincial Welding Material Testing Center, as shown in Table 4. For the convenience of comparison, the mechanical properties of some internationally famous similar brands of electrodes are also included in Table 4.

Table 4 The mechanical performance comparison of the present invention and some internationally famous similar brand electrodes Electrode grade place of origin BMPa бs MPa б5(%) Akv, J(-30℃) KOBE8010 Japan 590 490 27 52 TSU8010 Japan 630 550 27 80 OK22.47 Sweden 590 480 26 54 Pipeweld8010 Sweden 595 515 twenty four 45 Shieldarc70 U.S. 600 515 25 56 Thyssence180 Germany 600 510 25 50 THJ555E this application 605 510 28 90(87 89 95)

It can be seen from Table 4 that the welding rod has reached the level of similar international advanced products - Kobelco KOBE8010 of Japan and Lincoln's E8010-G welding rod of the United States. Similar well-known welding rods at home and abroad.

(2) Welding process performance of the present invention

The technological performance of the present invention was tested according to the provisions of "Evaluation Method for Electrode Welding Process Performance" JB/T8423-96, and the results are shown in Table 5.

Table 5 The present invention and the technological performance comparison of some international famous similar brand electrodes Electrode grade place of origin Length mm Welding current A Arc breaking length mm Slag removal rate% Restrike time S Splash rate% Stomata Weld Forming KOBE8010 Japan 350 135 19.3 100 10 4.1 none fine TSU8010 Japan 350 135 19.5 100 9 4.0 none fine OK22.47 Sweden 350 135 18.9 99 10 3.9 none fine Pipeweld8010 Sweden 350 135 19.2 99 9 4.0 none fine Shieldarc70 U.S. 350 135 19.8 100 10 3.8 none fine Thyssence180 Germany 350 135 19.8 100 10 3.9 none fine TH·J555E this application 400 135 20.1 100 11 3.8 none fine

It can be seen from Table 5 that the welding rod has excellent process performance, fast welding speed, good arc ignition and re-strike performance, good front and back molding, easy slag removal, and small spatter. The comprehensive process performance has reached the advanced level of similar foreign products.

(3) pipe joint performance test of the present invention

Select 20 steel pipes, the specification is φ377×10, and the groove angle of the pipe joint is 65°. During the test, TH J555E electrode must be used to deposit 5 layers to weld the groove completely. The performance test of the pipe joint is in accordance with the standard API1104-88 of the American Petroleum Institute. According to relevant regulations, the test results are shown in Table 6 and Table 7.

Table 6 Test results of mechanical properties of test pipe joints (TH J555E φ4) Stretching test Bending test Notch Hammer Break Test Tensile strength (Mpa) Fracture location assessment project Pressure head diameter (mm) Bending Angle(0) assessment Stomata none Comprehensive assessment qualified 585 base material qualified Positive bend 89 180 qualified Slag 564 base material 541 base material reverse bend 89 180 qualified Not fused 510 base material Incomplete penetration

Table 7 Surface quality inspection results of test pipe joints Testing method Welding Inspection Dimensions Assembly size Groove Angle(0) Blunt edge(mm) Clearance(mm) Misalignment(mm) Width (mm) 65-70 1.5-2 2.0 0.7 10-11.5 Test result (mm) Weld reinforcement Weld reinforcement difference Weld width width difference Back weld reinforcement 0-1.5 1.5 12-12.5 0.5 0-1.0 crack Not fused Slag Incomplete penetration Weld Dimples on the back Misalignment undercut none none none none none none 0-0.2 <0.74×35 Assessment: Qualified (API1104-88)

It can be seen from Table 6 and Table 7 that the pipe joint welding performance of TH J555E electrode meets the requirements of the American Petroleum Institute standard API1104-88, and can fully meet the requirements of the pipe's full-position downward welding operation.

In short, the composition and mechanical properties of the high-cellulose type (TH J555E) electrode applied in this paper meet the requirements of E5510 in the national standard GB/T5118-1995, and it has excellent low-temperature toughness. The low-temperature Charpy notched impact value Akv (-30°C) reaches 90J, It is superior to similar famous welding rods at home and abroad. The welding rod has excellent process performance, and the welding performance of the pipe joint of the welding rod meets the requirements of the American Petroleum Institute standard API1104-88. It can fully meet the requirements of downward welding operation in all positions of the pipe, with fast welding speed, good arc ignition and re-strike performance, good front and back molding, easy slag removal, small spatter, and has the ability to apply welding current (see Table 8). The characteristics of welding defects such as no redness of the coating and no pores in the weld during welding. That is to say, the technical performance of TH J555E electrode has reached the advanced level of similar foreign electrodes (the level of internationally famous brand electrodes such as Kobelco KOBE8010 of Japan, E8010-G electrode of Lincoln of the United States), and its low temperature toughness is better.

Table 8 Welding current of TH J555E electrode welding rod TH J555E φ3.2 60-90 φ4.0 110-150 φ4.8 150-180

Claims (3)

1, a kind of high cellulose type welding rod, comprise welding core, coating and bonding agent, it is characterized in that described coating composition and content (weight percent) are respectively: Microcrystalline fiber: 29-31% Starch: 1~3% Bamboo powder: 3-5% Rutile: 10～12% Titanium dioxide: 1～3% Lingbitite: 2～4% Sepiolite: 10～12% Mica: 2～4% Iron powder: 5～7% Nickel powder: 3.5～4.5% Ferromolybdenum: 1～1.5% Medium carbon ferromanganese: 6-8% Rare earth ferrosilicon: 2~3.5% Iron sand: 8～10% Magnesia: 4-6%. 2. A high-cellulose welding rod according to claim 1, characterized in that the contents (percentage by weight) of said components are respectively: Microcrystalline Fiber: 30% Starch: 1% Bamboo powder: 4% Rutile: 12% Titanium dioxide: 2% Magnolia: 3% Meerschaum: 11% Mica: 3% Iron powder: 5% Nickel powder: 4% Ferromolybdenum: 1.5% Medium carbon ferromanganese: 7% Rare earth ferrosilicon: 2.5% Iron Sand: 8% Magnesia: 6%. 3. A high-cellulose electrode according to claim 1 or 2, characterized in that the adhesive has a modulus of 2.8-3.0M, a potassium-sodium ratio of 2:1, and a concentration of 40.5°Be'- Water glass of 43.0°Be'.