（HY- Technical Center）
Hastelloy is a kind of nickel-based alloy. It is mainly divided into three series of B, C and G. It is mainly used for strong corrosion of iron-based Cr-Ni or Cr-Ni-Mo stainless steel and non-metal materials. In the case of sexual media, it has been widely used in many fields such as petroleum, chemical industry and environmental protection. The grades and typical use cases are shown in the table below.
|Grade||N10001 (B)||N10 276 (C- 276 )||N06007 (G )|
|N10665(B-2)||N06022 (C-22)||N06985 (G-3)|
|Main alloy element||Ni-Mo||Ni-Cr-Mo||Ni-Cr-Fe-Mo|
|Typical use||Reducing medium such as hydrochloric acid||Mixed medium with oxidation and reduction||Phosphoric acid, sulfuric acid, sulfate, etc.|
In order to improve the corrosion resistance and cold and hot processing properties of Hastelloy, Hastelloy has undergone three major improvements, and its development process is as follows:
B series : B → B-2 (00Ni70Mo28) → B-3
C series : C → C-276(00Cr16Mo16W4) → C-4(00Cr16Mo16) → C-22 (00Cr22Mo13W3) → C-2000(00Cr20Mo16)
G series : G → G-3 (00Cr22Ni48Mo7Cu) → G-30 (00Cr30Ni48Mo7Cu)
The most widely used materials are the second generation materials N10665 (B-2), N10276 (C-276), N06022 (C-22), N06455 (C-4) and N06985 (G-3). The third generation materials N10675 (B-3), N10629 (B-4), and N06059 (C-59) are in the promotion stage. Due to the advancement of metallurgical technology, in recent years, a number of grades of so-called “super stainless steel” containing ~6% Mo have appeared, replacing the G series alloys, which has led to a rapid decline in the production and use of G-series alloys.
Ⅱ： the typical Hastelloy chemical composition:
|Chemical composition of the material|
Ⅲ：the mechanical properties：
The mechanical properties of Hastelloy are very prominent. It has high strength and high toughness, so it has certain difficulty in machining, and its strain hardening tendency is very strong. When the deformation rate reaches 15%, it is about 18-8. Double the stainless steel. There is also a medium temperature sensitization zone in Hastelloy, and its sensitization tendency increases with the increase of deformation rate. When the temperature is high, Hastelloy absorbs harmful elements and deteriorates its mechanical properties and corrosion resistance.
|Mechanical properties of materials|
|Grade||standard||thickness（mm)||σb(Mpa)||σ0.2(Mpa)||δ 5 (%)||Hardness (HRB)|
|N l 0665(B-2)||ASTM B333-1998||≤4.76
|N10276(C-276)||AST M B575-1999||≤63.5
0.51- 63 .5
|N06007(G-3)||ASTM B 582-1997|
Ⅳ：commonly used Hastelloy
First: Hastelloy B-2 alloy
A: Corrosion resistance
Hastelloy B-2 alloy is a Ni-Mo alloy with very low carbon content and silicon content. It reduces the precipitation of carbides and other phases in the weld and heat affected zone, thus ensuring even under welding conditions. Also has good corrosion resistance. It is well known that Hastelloy B-2 alloy has excellent corrosion resistance in various reducing media, and can withstand any temperature at any pressure and corrosion of any concentration of hydrochloric acid. It has excellent corrosion resistance in non-aerated medium-concentration non-oxidizing sulfuric acid, various concentrations of phosphoric acid, high-temperature acetic acid, formic acid and other organic acids, bromic acid and hydrogen chloride gas. At the same time, it is also resistant to corrosion by halogen catalysts. Therefore, Hastelloy B-2 alloys are commonly used in a variety of demanding petroleum and chemical processes, such as distillation, concentration of hydrochloric acid; alkylation of ethylbenzene and production of low pressure carbonylation of acetic acid. However, in the industrial applications of Hastelloy B-2 alloy for many years:
Hastelloy B-2 alloy has two sensitized zones that have considerable influence on intergranular corrosion resistance: high temperature zone of 1200~1300°C and medium temperature zone of 550~900°C;
The weld metal and heat affected zone of Hastelloy B-2 alloy are precipitated along the grain boundary due to dendrite segregation, which makes it more sensitive to intergranular corrosion;
Hastelloy B-2 alloy has poor thermal stability at medium temperature. When the iron content in the Hastelloy B-2 alloy falls below 2%, the alloy is sensitive to the transformation of the beta phase (i.e., the Ni4Mo phase, an ordered intermetallic compound). When the alloy stays in the temperature range of 650~750 °C for a little longer, the β phase is generated instantaneously. The presence of the β phase reduces the toughness of the Hastelloy B-2 alloy, making it sensitive to stress corrosion, and may even cause the Hastelloy B-2 alloy to be used in the production of raw materials (such as during hot rolling) and in the manufacturing process of equipment (eg The overall heat treatment of the Hastelloy B-2 alloy equipment after welding and the Hastelloy B-2 alloy equipment are cracked in the service environment. Nowadays, the standard test methods for the intergranular corrosion resistance of Hastelloy B-2 alloys designated by China and the rest of the world are all atmospheric boiling hydrochloric acid method, and the evaluation method is weight loss method. Since the Hastelloy B-2 alloy is an alloy resistant to hydrochloric acid corrosion, the atmospheric pressure boiling hydrochloric acid method is relatively insensitive to the intergranular corrosion tendency of the Hastelloy B-2 alloy. Domestic research institutes have studied the Hastelloy B-2 alloy by high temperature hydrochloric acid method and found that the corrosion resistance of Hastelloy B-2 alloy depends not only on its chemical composition, but also on the control process of its thermal processing. When the thermal processing technology is not properly controlled, the Hastelloy B-2 alloy not only grows in grain size, but also exhibits a high Mo σ phase in the intergranular phase. At this time, the resistance of intergranular corrosion of Hastelloy B-2 alloy is significantly reduced. In the high-temperature hydrochloric acid test, the grain boundary etching depth of the coarse-grain plate and the normal plate is about one time difference.
The physical properties of the Hastelloy B-2 alloy are shown in the table below. Density: 9.2g/cm3, Melting point: 1330~1380°C, magnetic permeability: (°C, RT)≤1.001
|Physical properties of the material|
|Specific Heat Capacity
|Heat transfer coefficient
( µ Ω cm)
( Gpa )
|Thermal expansion coefficient from room temperature to T(106/K)|
C： the chemical composition：
D: mechanical properties
The general mechanical properties of the Hastelloy B-2 alloy are shown in the following two tables. Minimum mechanical properties at room temperature (refer to DIN/ASTM standards)
|Cold rolled strip||≤5||340||380||755||40||250||127|
|Hot rolled sheet||5- 65||214|
Minimum mechanical properties at high temperatures:
E: Manufacturing and heat treatment
Heating For Hastelloy B-2 alloys, it is important to keep the surface clean and away from contaminants before and during heating. If the Hastelloy B-2 alloy is heated in an environment containing sulfur, phosphorus, lead or other low-melting metal contaminants, it will become brittle. The sources of these contaminants mainly include marker marks, temperature indicating paints, greases and liquids. Smoke. The flue gas must have low sulfur content; for example, the sulfur content of natural gas and liquefied petroleum gas does not exceed 0.1%, the sulphur content of urban air does not exceed 0.25 g/m3, and the sulfur content of fuel oil does not exceed 0.5%. The gas environment of the heating furnace is required to be a neutral environment or a lightly reducing environment, and it is not possible to fluctuate between oxidizing property and reducing property. The flame in the furnace cannot directly impact the Hastelloy B-2 alloy. At the same time, the material should be heated to the required temperature at the fastest heating rate, that is, it is required to first raise the temperature of the heating furnace to the required temperature, and then put the material into the furnace for heating.
Thermal processing Hastelloy B-2 alloy can be hot worked in the range of 900~1160 °C. After processing, it should be quenched with water. In order to ensure the best corrosion resistance, it should be annealed after hot working.
Cold working The cold-worked Hastelloy B-2 alloy must be solution treated. Since it has a much higher work hardening rate than austenitic stainless steel, the forming equipment should be carefully considered. If a cold forming process is performed, then interstage annealing is necessary. When the amount of cold work deformation exceeds 15%, it should be solution treated before use.
Heat treatment The solution heat treatment temperature should be controlled between 1060 and 1080 °C. After water quenching or material thickness of 1.5mm or more, it can be quickly air-cooled to obtain the best corrosion resistance. Precautions must be taken to clean the surface of the material during any heating operation. Harbinite materials or equipment parts should pay attention to the following problems when heat treatment: in order to prevent heat treatment deformation of equipment parts, stainless steel reinforcement ring should be used; temperature, heating and cooling time should be strictly controlled; heat treatment parts before furnace installation Pretreatment is carried out to prevent thermal cracking; after heat treatment, the heat-treated part is 100% PT; if heat cracking occurs during the heat treatment, the welder needs to be repaired after grinding, and a special repair welding process is adopted.
Descaling The oxides on the surface of the Hastelloy B-2 alloy and the stains near the weld are polished with a fine grinding wheel. Since the Hastelloy B-2 alloy is sensitive to oxidizing media, more nitrogen-containing gases are produced during the pickling process.
Machining Hastelloy B-2 alloy should be machined in an annealed state, and it should have a clear understanding of its work hardening. For example, a slower surface cutting speed is required compared to standard austenitic stainless steel. The hardened layer requires a large amount of feed and the tool is in continuous operation.
Welding of Hastelloy B-2 alloy weld metal and heat-affected zone due to easy precipitation of β phase leads to lean Mo, which is prone to intergranular corrosion. Therefore, the welding process of Hastelloy B-2 alloy should be carefully formulated and strictly controlled. . The general welding process is as follows: ERNi-Mo7 for welding consumables; GTAW for welding method; temperature between control layers is not more than 120 °C; diameter of welding wire is φ2.4, φ3.2; welding current is 90~150A. At the same time, before welding, the welding wire, the bevel of the welded part and the adjacent parts should be decontaminated and degreased. The heat transfer coefficient of Hastelloy B-2 alloy is much smaller than that of steel. If a single V-shaped groove is used, the groove angle should be around 70°, and a lower heat input is used. Post-weld heat treatment eliminates residual stress and improves stress corrosion crack resistance.
Second: Hastelloy C-276 alloy
A: Corrosion resistance
The Hastelloy C-276 alloy belongs to a nickel-molybdenum-chromium-iron-tungsten-based nickel-based alloy. It is the most resistant of modern metal materials. Mainly resistant to wet chlorine, various oxidizing chlorides, chloride solutions, sulfuric acid and oxidizing salts, have good corrosion resistance in low temperature and medium temperature hydrochloric acid.
Therefore, in the past 30 years, in the harsh corrosive environment, such as chemical, petrochemical, flue gas desulfurization, pulp and paper, environmental protection and other industrial fields have a wide range of applications. Various corrosion data for Hastelloy C-276 alloys are typical, but they cannot be used as specifications, especially in an unidentified environment, which must be tested before they can be selected. There is not enough Cr in the Hastelloy C-276 alloy to resist corrosion in strong oxidizing environments, such as hot concentrated nitric acid. The production of this alloy is mainly for the chemical process environment, especially in the presence of mixed acid, such as the discharge pipe of the flue gas desulfurization system. The table below shows the corrosion comparison test of the four alloys in different environments. (All welding specimens are self-fluxing tungsten argon arc welding)
|Corrosion comparison test of four metals in different environments|
|corrosion rate （mm/a）|
|Base metal sample||welded sample||Base metal sample||welded sample||Base metal sample||Base metal sample||welded sample|
|20% acetic acid||0.003||0.003||0.0036||0.0018||0.0076||0.013||0.006|
|45% formic acid||0.277||0.262||0.116||0.142||0 13||0.07||0.049|
|10% oxalic acid||1.02||0.991||0.277||0.274||0.15||0.29||0.259|
|20% phosphoric acid||0.177||0.155||0.007||0.006||0.001||0.001||0.0006|
|10% sulfuric acid NH2SO3H||1.62||1.58||0.751||0.381||0.12||0.07||0.061|
|10% sulfuric acid H2SO4||9.44||9.44||2.14||2.34||0.64||0.35||0.503|
|10% sodium bicarbonate||1.06||1.06||0.609||0.344||0.10||0.07||0.055|
Hastelloy C-276 alloy can be used as a flue gas desulfurization component for coal-fired systems. C-276 is the most corrosion-resistant material in this environment. The table below shows the corrosion comparison test of C-276 alloy and typical 316 in the “green death” solution of the flue gas simulation system. Corrosion comparison test in green death solution
|“ Green death＂
Corrosion comparison test in solution
|“green death” solution
|7% sulfuric acid||damage||0.67|
|3% hydrochloric acid|
It can be seen from the above table that C-276 alloy has good corrosion resistance to mixed acid and salt solutions with chloride ions. The addition of Cr, Mo and W in the Hastelloy C-276 alloy greatly improves the p-etching resistance and crevice corrosion resistance of the C-276 alloy. C-276 alloy is considered to be inert in seawater environments, so C-276 is widely used in marine, salt water and high chlorine environments, even at low pH values. The table below compares the crevice corrosion of four metals in a solution of 6% FeCl3 (performed in accordance with ASTM Standard G-48).
|Alloy||Crevice corrosion temperature|
|AL- 6 XN||113||45|
The high content of Ni and Mo in C-276 alloy is also very resistant to chloride ion stress corrosion cracking. The following table shows the stress corrosion cracking test of four metals in different chloride ion solutions.
Chloride ion stress corrosion crack test
|Test solution||Bending U-shaped test time ( Hours ) and test results|
B: Physical properties:
The physical properties of C-276 alloy are shown in the following table: Density: 8.90g/cm3, Specific heat: 425J/kg/k, Modulus of elasticity: 205Gpa (21°C)Thermal conductivity:
|The temperature||Thermal conductivity|
Linear expansion coefficient:
|Linear expansion coefficient|
|From 21 ℃ to||Linear expansion coefficient|
C: Mechanical property:
Linear expansion coefficient III, mechanical properties The tensile test results of a typical C-276 alloy are shown in the following table. The material is annealed at 1150 ° C and quenched with water.
Mechanical property test value
|The yield strength
|-196||5 65||965||4 5|
Cold deformation of the C-276 alloy increases its strength. In the impact test, the V-groove impact specimen is made of 10mm thick sheet (the sheet is to be annealed). If the specimen is welded, it will show a certain temperature in the same temperature range. Flexibility, this is because of the weld. The results of the sheet impact test are shown in the table below.
|Test temperature （°C ）||Impact energy of v-groove sample (J)|
C-276 alloy has similar formability to ordinary austenitic stainless steel. However, since it is stronger than ordinary austenitic stainless steel, there is more stress during the cold forming process. In addition, this material has a much faster work hardening speed than ordinary stainless steel, so mid-way annealing is required during extensive cold forming processes.
D: welding and heat treatment:
The welding performance of C-276 alloy is similar to that of ordinary austenitic stainless steel. Before using a welding method to weld C-276, measures must be taken to minimize the corrosion resistance of the weld and heat affected zone, such as tungsten. Gas shielded welding (GTAW), metal gas shielded welding (GMAW), submerged arc welding or other welding methods that minimize the corrosion resistance of welds and heat affected zones. However, it is not suitable for welding methods such as oxyacetylene which may increase the carbon content or silicon content of the weld and heat affected zone of the material. For the selection of welded joint forms, reference can be made to the successful experience of the ASME Boiler and Pressure Vessel Code for C-276 welded joints.
The welding groove is preferably machined, but the machining will bring about work hardening, so it is necessary to polish the machined groove before welding. A suitable heat input speed is used for welding to prevent the occurrence of hot cracks. In most corrosive environments, the C-276 can be used in the form of welded parts.
However, in very demanding environments, C-276 materials and weldments are solution heat treated to achieve the best corrosion resistance. The welding of C-276 alloy can be selected as the welding material or filler metal. If it is required to add certain components to the weld of C-276, such as other nickel-based alloys or stainless steel, and these welds will be exposed to corrosive environments, then the welding rod or welding wire used for welding is required to have the base metal Corrosion resistant performance. The solution heat treatment of Hastelloy C-276 alloy material comprises two processes;
Heating at 1040 ° C ~ 1150 ° C;
Rapid cooling to black state (about 400 °C) within two minutes, so that the treated material has good corrosion resistance. Therefore, it is ineffective to perform stress relief heat treatment only on Hastelloy C-276 alloy. Before the heat treatment, it is necessary to clean all the dirt which may generate carbon during the heat treatment, such as oil stain on the surface of the alloy. The surface of C-276 alloy will produce oxides during welding or heat treatment, which will reduce the Cr content in the alloy and affect the corrosion resistance, so it should be surface cleaned. A stainless steel wire brush or a grinding wheel can be used, followed by immersion in a mixture of nitric acid and hydrofluoric acid in an appropriate ratio, and finally rinsed with water.
Third: Hastelloy C-22 Alloy
A： corrosion resistance and product form
Hastelloy C-22 alloy is a Ni-Cr-Mo alloy which is highly resistant to pitting, crevice corrosion, intergranular corrosion and stress corrosion cracking. The combination of Ni, Cr, Mo and W allows the Hastelloy C-22 alloy to have excellent corrosion resistance over a wide range of oxidizing and reducing environments. As can be seen from the table below, Hastelloy C-22 alloy has outstanding corrosion resistance in most demanding environments, and it is resistant to precipitation of intergranular carbides and generation of multiple phases in welding operations or forging operations.
Hastelloy C-22 alloy is widely used in flue gas desulfurization systems, bleaching systems in the pulp and paper industry, waste incinerators, chemical plants, pharmaceutical plants and radioactive waste storage industries. Hastelloy C-22 alloy has high strength and good ductility, weldability and formability, so it is consistently detailed in ASME and ASTM standards. Its material products are in the form of plates, strips, pipes, rods and forgings.
B: chemical composition
|chemical elements||Standard range of UNS (weight percentage)|
C: Physical properties:
Physical properties of C-22 alloy with typical chemical composition in annealed state
|Density at 22 ° C||8.62||g/cm3|
|Melting temperature range||1354~1388||℃|
|Heat transfer coefficient at 53 ° C||9.4||W/m.K|
|Thermal expansion coefficient of 20~217°C||12.44||μm/m/℃|
|Specific heat capacity at 22 ° C||422||J/kg-℃|
|Modulus of elasticity at 22 ° C||207||Gpa|
D: welding performance：
Hastelloy C-22 alloy has very good welding performance. It can be easily welded by tungsten gas shielded welding, metal gas shielded welding, submerged arc welding, etc. The filler metal requires a matching chemical composition. V. Mechanical Properties Hastelloy C-22 alloy has good thermal processing properties. The mechanical properties at room temperature in the annealed state are shown in the table below. The thickness of the test sheet ranges from 4.76 mm to 50.8 mm.
Fourth: Hastelloy C-59 Alloy
C-59 is an ultra-low carbon Ni-Cr-Mo alloy with excellent corrosion resistance and high mechanical strength. Its nature has the following:1. Wide corrosion resistance under oxidizing and reducing conditions;2. It has good resistance to pitting and crevice corrosion, and has immunological properties for chlorine-induced stress corrosion cracking.3. Good corrosion resistance to inorganic acids such as nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid and sulfuric acid hydrochloric acid;4. It also has good corrosion resistance to inorganic acids containing impurities;5. Good corrosion resistance to any concentration of hydrochloric acid below 40 °C;6. It is allowed to be used on pressure vessels between -196-450 °C;7. It is used under the sour gas environment by the NACE standard MR-01-75 VII. (NACE is the National Electronic Advisory Board for the United States and India)
B: chemical composition
|chemical elements||Standard range of UNS (weight percentage)|
C: corrosion resistance and application
C-59 alloy is a Ni-Cr-Mo alloy with very low carbon content and silicon content. It does not tend to produce mesophase during hot working and welding. Therefore, this alloy can be used for oxidation in chemical processes. Sexual and reducing media. Due to the high content of Ni, Cr and Mo, C-59 has good corrosion resistance to chloride ions. It has been confirmed in standard corrosion tests involving oxidizing environments that C-59 alloys have higher performance than other Ni-Cr-Mo alloys. C-59 alloy has good corrosion resistance in reducing environment. For example, the corrosion rate in 10% boiling sulfuric acid solution is about 1/3 of that of other Ni-Cr-Mo alloy, and it is also good in hydrochloric acid environment. Corrosion resistance. The following two tables are for different corrosion tests.
Comparison of C-276 and C-59 tests
|Test medium||C276(corrosion rate(mm/a）||C59(corrosion rate(mm/a）|
|ASTM G28A boil for 24 hours||5~6||0.625|
|ASTM G28B boil for 24 hours||1.5||0.1|
Corrosion test of three different alloys in different solutions
|Test medium||C276(corrosion ratemm/a）||C59(corrosion ratemm/a）||Inconel625(corrosion ratemm/a）|
|10%H2SO4 boil for 3*7 days
|Cl（NaCl） 3*7 days 80℃
|Cl（NaCl） 3*7 days 50℃||0.42||0.38||0.65|
|98.5%H2SO4 3*7 days 150℃/200℃||/||0.28/0.15||/|
The following table shows the CPT and CCCT tests for the three alloys
Test solution: 7 Vol.% H2SO4 + 3 Vol. % HCl + 1% CuCl2 + 1% FeCl3-6H2O (green dead solution), after 24 hours of aging, increasing at 5 °C.
C-59 alloy in chemical, petrochemical, energy and environmental engineering.
Chlorine-containing organic process equipment, especially in the presence of halogenated acidic catalysts;
Dissolution and bleaching system equipment in the pulp and paper industry;
Preheaters, valves, impellers and other components of incinerators and flue gas desulfurization systems;
Acid gas treatment system equipment and components;
Acetic acid and acetic anhydride reactors;
Sulfuric acid condenser.
D: Physical properties:
Density: 8.6g/cm3 Melting point range: 1310-1360°C Permeability: 20°C, (RT)≤1.001 Physical properties at high temperature
|Physical properties at high temperatures|
|Temperature||Specific heat||Thermal conductivity||resistivity||Modulus of elasticity||The coefficient of thermal expansion from room temperature to T|
E: Mechanical Properties:
The following table shows the mechanical properties of C-59 alloy in solution treatment state. Minimum mechanical properties at room temperature.
*Mechanical values according to the German national standard VdTüV data 505 The following table is based on the German national standard VdTüV data 505, the mechanical properties at high temperatures.
|Tensile Strength||elongation δ5|
For materials with a plate thickness between 30-50mm, the yield strength value should be reduced by 20MPa 2 for bars only Maximum allowable stress ：
Welded joints have a weld coefficient of 0.85
F: V-shaped groove impact:
work Average value at room temperature: ≥225J/cm2
under-196°C: ≥200 J/cm2
G: crystal structure:
C-59 alloy is a face-centered cubic crystal structure.
H: crystal structure:
C-59 alloy can be easily processed by common manufacturing processes.
Heating C-59 alloy should not be in contact with any contaminants before and during heat treatment. Heating in an environment containing S, P, Pb and other low melting metals will degrade the performance of the C-59 alloy. The main sources of pollutants are marking pen marks, temperature indicating paint, chalk, lubricating grease, fuel, etc. The sulphur content of the furnace fuel must be low, the sulphur content of the natural gas must be less than 0.1% (mass), and the sulphur content of the fuel oil should not exceed 0.5%. The furnace gas environment should be slightly oxidizing and should not fluctuate between oxidizing and reducing properties. Do not allow the flame to directly impact the alloy material.
Thermal processing C-59 alloy can be hot processed between 950-1180 °C. Cool down with water. Annealing after hot working ensures good corrosion resistance of the material.
Cold working The annealed C-59 alloy can be used for cold working. The work hardening rate of C-59 alloy is very high, and the requirements for forming equipment are higher. Inter-process annealing is necessary when cold deformation processing is performed.
Heat treatment The solution heat treatment temperature should be 1100-1180 ° C, preferably 1120 ° C. Water cooling is the basic point to ensure the best corrosion resistance of the material. The surface of the material must be clean during any thermal operation.
Descaling The oxide near the C-59 alloy weld is much tighter than other stainless steels and can be cleaned with a fine grinding wheel. Before pickling, oxides, stains, etc. on the surface of the material can be polished with a fine grinding wheel or a stainless steel wire brush.
Machining Machining C-59 alloy should be in a solution treatment state. Due to its high work hardening rate, a lower surface cutting speed is used relative to the low alloy austenitic stainless steel, and the amount of feed is large to ignore the harder surface. At the same time, the tool should be in continuous operation.
I: crystal structure:
When welding nickel-based alloys, the following procedures must be observed:
Workplace The welding field of C-59 alloy is independent. It is best to be separated from the carbon steel processing site, and there should be no airflow disturbance.
Dressing welding should be worn with leather gloves and overalls.
Processing tools and mechanical tools to use nickel-based alloy special tools, manufacturing and processing machinery such as: shearing machine, coiling machine, pressing machinery, etc., the work surface should be covered with felt, cardboard, plastic, etc., to prevent C-59 The surface of the alloy is pressed into contaminants during processing, resulting in eventual corrosion.
Cleaning The cleaning of the weld area of the base metal and the cleaning of the filler metal should use acetone.
Groove preparation C-59 alloy welding groove forming can be mechanical methods, such as turning, grinding or planing; plasma cutting is also possible, but the groove after cutting should be polished, and can not Overheating near the groove.
The groove angle is generally after welding should be brushed with stainless steel wire to remove the oxidation part. The general difference between nickel-based alloys and special stainless steels over ordinary carbon steels is that they have a lower heat transfer coefficient and a higher coefficient of thermal expansion. The welding leg is large (1-3 mm), and the groove angle is about 60-70°, mainly because the molten metal of C-59 alloy has high viscosity, and its tendency to shrink after welding is relatively large.
Arc ignition The arc ignition can only be carried out in the weld area to be welded, and it should not be on the finished welding parts to avoid the corrosion resistance.
Welding Process C-59 alloy can be welded by various conventional welding processes, such as: TIG/GTAW, MIG/MAG, manual metal welding, plasma arc welding, etc. However, cleaning before welding is necessary.
Welding parameters and related influencing factors Care should be taken to select the heat input during welding.
Generally, a lower heat input should be used, and the interlayer temperature should not exceed 150 °C. At the same time, a thinner bead welding process is used.