(1) United States Hastelloy International Inc. (Haynes International, Inc.)'s Predecessor, Haynes Stellite Work (Heart of Midlothian cobalt chromium tungsten factory) was founded in 1921 in the United States Indiana Kokomo, have elapsed since the 91-year history, ninety years experience in production and research in innovation and invention, resulting in the field of high-alloy Wenju in the world. Haynes Haynes International's focus on the production and development. Is mainly engaged in high-quality anti-corrosion and high temperature nickel - cobalt alloy development and production. At the same time, the company's expert technical staff on a global scale to provide further customer service and technical support. Haynes Company's service centers and branch offices be able to offer our customers timely and plates, rods, tubes, pipes, forgings, flanges and connectors, etc..
(2), Hastelloy (Hastelloy alloy)
Hastelloy alloy is a nickel-based alloys, the key is divided into B, C, G 3 series, which is mainly used for iron-based Cr-Ni or Cr-Ni-Mo stainless steel, non-metallic materials can not be used strong corrosion medium occasions, in foreign countries has been widely used in petroleum, chemical industry, environmental protection and many other fields.
Hastelloy Alloy (Hastelloy alloy)
一．Are currently divided into B, C, G 3 series, which is mainly used for iron-based Cr-Ni or Cr-Ni-Mo stainless steel, non-metallic materials can not use the occasion of strong corrosive medium.
Hastelloy Alloy
In order to improve the corrosion resistance of Hastelloy and cold, thermal processing performance, Hastelloy has carried out three major improvements, and its development process is as follows:
B → B-2(00Ni70Mo28) → B-3 B Series: B → B-2 (00Ni70Mo28) → B-3
C → C-276(00Cr16Mo16W4) → C-4(00Cr16Mo16) → C-22 (00Cr22Mo13W3) → C-2000(00Cr20Mo16) C Series: C → C-276 (00Cr16Mo16W4) → C-4 (00Cr16Mo16) → C-22 (00Cr22Mo13W3) → C-2000 (00Cr20Mo16)
G → G-3（00Cr22Ni48Mo7Cu） → G-30(00Cr30Ni48Mo7Cu) G Series: G → G-3 (00Cr22Ni48Mo7Cu) → G-30 (00Cr30Ni48Mo7Cu)
Currently the most widely used is the second-generation materials, N10665 (B-2), N10276 (C-276), N06022 (C-22), N06455 (C-4) and N06985 (G-3).
2、the typical chemical composition of Hastelloy
The chemical composition of materials
Ni Cr Mo Fe C Si Co Mn PSWV Cu Nb+Ta Ni Cr Mo Fe C Si Co Mn PSWV Cu Nb + Ta
N10665 (B-2) based ≤ 1.0 26.0 ~ 30 ≤ 2.0 ≤ 0.02 ≤ 0.10 ≤ 1.0 ≤ 1.0 ≤ 0.04 ≤ 0.03
N10276 (C-276) Base 14.5 ~ 16.5 15.0 ~ 17.0 4.0 ~ 7.0 ≤ 0.01 ≤ 0.08 ≤ 2.5 ≤ 1.0 ≤ 0.04 ≤ 0.03 3.0 ~ 4.5 ≤ 0.035
N06007 (G-3) Base 21.0 ~ 23.5 6.0 ~ 8.0 18.0 ~ 21 ≤ 0.015 ≤ 1.0 ≤ 5.0 ≤ 1.0 ≤ 0.04 ≤ 0.03 ≤ 1.5 1.5 ~ 2.5 ≤ 0.50
3、 mechanical properties
The mechanical properties of Hastelloy is very prominent, and it has high strength and high toughness characteristics, so in machining have certain degree of difficulty, and its strong tendency to strain hardening, when the deformation rate of 15%, about 18-8 stainless steel double. Hastelloy exist in the temperature-sensitive of areas, the tendency of its sensitivity increases with the deformation rate increases. When the temperature is higher, Hastelloy makes it easy to absorb the harmful elements in the mechanical properties and corrosion resistance decreased.
Mechanical Properties of Materials
4、common Hastelloy
1: Hastelloy B-2 alloy (Hastelloy B-2 alloy)
1, corrosion resistance
Hastelloy B-2 alloy is a kind of very low carbon content and silicon content of the Ni-Mo alloy, which reduces in the weld metal and heat affected zone precipitation of carbides and other phases to ensure that even in the welded state also a good corrosion resistance.
As everyone knows, Hastelloy B-2 alloy in a variety of reductive medium has excellent corrosion resistance, and capability of any atmospheric pressure and temperature, any concentration of hydrochloric acid corrosion. Not inflated non-oxidizing medium concentration of sulfuric acid, various concentrations of phosphoric acid, high acetic acid, formic acid and other organic acids, bromate, and hydrogen chloride gas have excellent corrosion resistance, while it is also resistant to halogen catalyst for corrosion. Therefore, Hastelloy B-2 alloy is usually used in a variety of harsh petroleum, chemical processes, such as hydrochloric acid distillation, concentration; ethylbenzene alkylation and low-pressure oxo process of acetic acid production.
However, Hastelloy B-2 alloy in industrial applications for many years found that: (1) The existence of Hastelloy B-2 alloy against intergranular corrosion can have a considerable impact on the two-sensitized Area: 1200 ~ 1300 ℃ high temperature zone and 550 ~ 900 ℃ in the temperature zone; (2), Hastelloy B-2 alloy weld metal and heat affected zone due to dendrite segregation, intermetallic phase and carbide precipitation along the grain boundaries to intergranular corrosion susceptibility of the larger ; (3) Hastelloy B-2 alloy in warm less stable. When the Hastelloy B-2 alloy in the iron content of below 2%, the alloy of the β-phase (ie, Ni4Mo phase, an ordered intermetallic compound) changes in sensitivity. When the alloy in the 650 ~ 750 ℃ temperature range slightly longer residence time, β-phase is generated instantly. The existence of β phase reduces the Hastelloy B-2 alloy toughness, so that it becomes sensitive to the stress corrosion, or even result in Hastelloy B-2 alloy in the production of raw materials (such as the hot rolling process), equipment, manufacturing process (such as the Hastelloy B-2 alloy after welding equipment, the overall heat treatment) and Hastelloy B-2 alloy devices in service environment cracking. Today, our country and the world designated by the Hastelloy B-2 alloy resistance to intergranular corrosion test methods are the standard atmospheric pressure boiling hydrochloric acid method, evaluation method for weight loss. As the Hastelloy B-2 alloy is hydrochloric acid corrosion resistant alloy, therefore, atmospheric pressure boiling hydrochloric acid method test Hastelloy B-2 alloy intergranular corrosion tendencies are quite insensitive. Domestic research institutions with high temperature hydrochloric acid method, Hastelloy B-2 alloy study found that: Hastelloy B-2 alloy corrosion resistance depends not only on its chemical composition, but also depends on its thermal processing of the control process. When the thermal processing process control is not the time, Hastelloy B-2 alloy is not only grain growth and intergranular will be analysis of the σ phase with high Mo, this time, Hastelloy B-2 alloy resistance to intergranular corrosion noticeable performance degradation , in the high-temperature hydrochloric acid test, the coarse grain board and the normal grain-boundary etching plate about twice the depth difference of about.
Second, the physical properties of
Density: 9.2g/cm3, melting point: 1330 ~ 1380 ℃, magnetic permeability: (℃, RT) ≤ 1.001
3, the chemical composition
Chemical Composition
Ni Cr Fe C Mn Si Cu Mo Co PS Element Ni Cr Fe C Mn Si Cu Mo Co PS
0.4 1.6 26.0 Minimum margin 0.4 1.6 26.0
Maximum 1.0 2.0 0.01 1.0 0.08 0.5 30.0 1.0 0.02 0.010
5, manufacturing and heat treatment
1: Heating
For Hastelloy B-2 alloy, the heating process of heating the surface before and kept clean and away from pollutants is very important. If the Hastelloy B-2 alloy containing sulfur, phosphorus, lead, or other low melting point metal pollutants heated environment, it will become brittle, the source of these pollutants include marking pen marks, temperature indicator paint, grease and liquids, flue gas. The flue gas must be low sulfur content; for example: natural gas and liquefied petroleum gas sulfur content of less than 0.1% sulfur content of no more than urban air 0.25g/m3, fuel oil sulfur content of less than 0.5% shall be eligible.
Environmental requirements of the furnace gas is neutral light to restore the environment or the environment, and not in oxidizing and reducing volatility in between. Furnace flame can not be a direct impact on Hastelloy B-2 alloy. At the same time with the fastest heating rate required to achieve the material heated to the temperature, which called for the first heater temperature should rise to requirements of temperature, then heated material into the furnace.
2: Thermal Processing
Hastelloy B-2 alloy at 900 ~ 1160 ℃ within the thermal processing, processing should be after the water quenching. In order to ensure the best corrosion resistance, should be annealed after thermal processing.
3: cold
Cold of Hastelloy B-2 alloy must be solution heat treatment, owing to its much higher than the austenitic stainless steel work-hardening rate, there is forming equipment have to be carefully considered. If you perform a cold forming process, then there is the need for inter-stage annealing.More than 15% cold deformation, the use of solution heat treatment before.
4: Heat treatment
Solution heat treatment temperature should be controlled between 1060 ~ 1080 ℃, after water quenching or material thickness above 1.5mm can be quickly air-cooled to obtain the best corrosion resistance. In any heating operation, the material surface cleaning have to have a pre-preparedness. Hastelloy materials or equipment components during heat treatment should pay attention to the following questions: In order to prevent heat deformation of parts of the equipment should be made of stainless steel reinforcement ring; right loaded furnace temperature, heating and cooling time should be strictly controlled; loaded blast furnace, to heat-treatment cases pre-processing, preventing hot cracking; heat treatment, heat treatment pieces of 100% PT; in the heat treatment process such as generating heat cracks, after grinding, after eliminating those who need to repair welding, repair welding process to adopt specialized.
5: Descaling
Hastelloy B-2 alloy surface oxides and weld in the vicinity of the stain must be in order to fine grinding wheel, etc. clean.
As the Hastelloy B-2 alloy on the oxidative medium sensitive, so pickling process will produce more nitrogen-containing elements in gases.
6: Machining
Hastelloy B-2 alloy is necessary to anneal state machine processing, it should have a clear understanding of work-hardening, for example: relative to the standard austenitic stainless steel surface, to adopt a slower cutting speed, for the surface hardened layer should be adopted the larger the amount of feed and make knives are continuously working condition.
7: Welding
Hastelloy B-2 alloy weld metal and heat affected zone as a result of β-phase precipitates easily depleted Mo, and thus are prone to intergranular corrosion, therefore, Hastelloy B-2 alloy welding process should be carefully designed and strictly controlled. General welding process is as follows: Welding selected ERNi-Mo7; Welding GTAW; control layer between the temperature of not greater than 120 ℃; wire diameter φ2.4, φ3.2; welding current of 90 ~ 150A. Meanwhile, before welding, wire, welded parts groove and the adjacent parts of decontamination should be carried out degreasing treatment.
Hastelloy B-2 alloy thermal conductivity is much smaller than steel, such as the selection of a single V-groove, the groove angle of 70 ° to about a lower amount of heat input. Through the post-weld heat treatment can eliminate the residual stress and to improve the performance of anti-stress corrosion cracking.
2: Hastelloy C-276 alloy (Hastelloy C-276 alloy)
1, corrosion resistance
Hastelloy C-276 alloy are nickel - Molybdenum - Chromium - Iron - Tungsten-nickel-based alloys. It is the most corrosion resistant metal material in modern kind. The main moisture chlorine, a variety of oxidizing chloride, chloride salts, sulfuric acid and oxidizing salt, hydrochloric acid at low temperature with the temperature are in very good corrosion resistance.Thus, nearly three decades, corrosion in harsh environments, such as chemical, petrochemical, flue gas desulfurization, pulp and paper, environmental protection and other industries with a wide range of applications.
Hastelloy C-276 alloy has a variety of corrosion data is typical, but it can not be used as a norm, especially in the unknown environment, must be tested before they can selection. Hastelloy C-276 alloy does not have enough resistance to strong oxidizing Cr to the corrosion environment, such as hot concentrated nitric acid. Production of this alloy is mainly for the chemical process environment, especially the existence of mixed acid situations, such as flue gas desulfurization system, discharge tubes. The following table shows four kinds of alloys in different environments on the corrosion of comparative test. (All welded specimens using a self-melting GTAW)
Four kinds of metal corrosion in different environments comparative test
Test environment (boiling) corrosion rate (mm /)
A typical 316 AL-6XN Inconel625 C-276
Basic metals, basic metals specimen welded specimens welded specimen specimen specimen of basic metals Basic metals welded specimen specimen
20% acetic acid 0.003 0.003 0.0036 0.0018 0.0076 0.013 0.006
formic acid 0.277 0.262 0.116 0.142 0.13 0.07 0.049
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% of the amino acid 1.62 1.58 0.751 0.381 0.12 0.07 0.061
10% sulfuric acid 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 coal-fired flue gas desulfurization system components, in such an environment C-276 is the most corrosion resistant materials.The following table is a typical C-276 alloy and 316 in the flue gas simulation system for "green death" test solution, the corrosion contrast to the situation.
"Green Death" solution, the corrosion comparative test
"Green Death" solution (boiling) corrosion rate (mm / a)
A typical 316 C-276
7% sulfuric acid destruction 0.67
3% hydrochloric acid
1% CuCl2
1% FeCl3
Above table shows, C-276 alloy mixed with the acid chloride, salt solution has good corrosion resistance.
Hastelloy C-276 alloy Cr, Mo, W to join the C-276 alloy resistance to pitting and crevice corrosion capacity greatly increased. C-276C-276 alloy in marine environment was considered to be inert, so the C-276 has been widely applied in the ocean, salt water and high chlorine environment, even in strong acid under the low PH value. The following table shows four kinds of metal in 6% FeCl3 (according to ASTM standard G-48 implementation) solution, crevice corrosion occurred in contrast to the situation.
The occurrence of crevice corrosion
Alloy crevice corrosion is the temperature
°F °C ° F ° C
A typical 31627 2.5
AL-6XN 113 45
Inconel625 113 45
C-276 140 60
C-276 alloy in the high levels of Ni and Mo to stress corrosion cracking of chloride ion has a strong resistance to, the following table are four kinds of metal ions in different chlorine solution of stress corrosion cracking in the testing.
Chloride ion stress corrosion cracking test case
U-shaped bend specimen test solution test time (Hours) and test results
Typical 316 AL-6XN Inconel 625 C-276
42% MgCl2 (boiling) failed (24 hours) both (1000 hours) resistance (1000 hours) resistance (1000 hours)
33% LiCl (boiling) failed (100 hours) resistance (1000 hours) resistance (1000 hours) resistance (1000 hours)
26% NaCl (boiling) failed (300 hours) resistance (1000 hours) resistance (1000 hours) resistance (1000 hours)
Second, the physical properties of
Density: 8.90g/cm3, specific heat: 425J/kg/k, elastic modulus: 205Gpa (21 ℃)
Third, mechanical properties
A typical C-276 alloy tensile test results in the following table, the material is annealed at 1150 ℃, and water quenching.
Mechanical properties of experimental values
Temperature (℃) yield strength σ0.2 (Mpa) tensile strength σb (Mpa) Elongation δ5 (%)
-196 565 965 45 -19,656,596,545
-101 480 895 50 -10,148,089,550
21 415 790 50 2141579050
93 380 725 50 9338072550
204 345 710 50 20,434,571,050
316 315 675 55 31,631,567,555
427 290 655 60 42,729,065,560
538 270 640 60 53,827,064,060
Pairs of C-276 alloy, cold deformation processing will increase its strength. In the impact test them, V-shaped groove with the impact of specimen 10mm thick plates (plate to go through annealing treatment), if the sample is used welded specimens, while at the same temperature range, it will show a certain degree of flexibility, this is because weld reasons. Plate impact test results are as follows in the table below.
Test temperature (℃) V-shaped groove specimen impact energy (J)
-196 245 -196,245
21 325 21325
200 325 200,325
C-276 alloy and common austenitic stainless steels have similar formability. However, because of its strength than conventional austenitic stainless steels should be large, so, in the cold forming process there would be even greater stress. In addition, this material work-hardening rate is much faster than conventional stainless steel, and therefore has extensive cold-forming process, to take mid-annealing treatment.
4, welding and heat treatment
C-276 alloy welding performance and common austenitic stainless steel similar to a welding method using the C-276 prior to welding, we must take steps to make the weld and heat affected zone, the smallest decline in corrosion resistance, such as tungsten gas shielded arc welding (GTAW), metal pole gas shielded arc welding (GMAW), submerged arc welding or some other can weld and heat affected zone the smallest decline in corrosion resistance welding method. But for such as oxy-acetylene welding, are likely to increase the weld metal and heat affected zone materials, carbon or silicon content is not suitable welding method used.
With regard to the choice of the form of welded joints, you can refer to ASME Boiler and Pressure Vessel Code of the C-276 welded joints of successful experience.
The best welding groove mechanical processing methods, but the machining will bring work-hardening, so machining before welding groove at polishing is necessary.
Welding heat input to adopt the appropriate speed, in order to prevent heat cracks.
In most corrosive environment, C-276 can be applied in the form of welded parts. However, in a very harsh environment, C-276 material and welding pieces of solution heat treatment to be carried out to obtain the best corrosion resistance.
C-276 alloy welding can choose their own materials or filler metal for welding. Such as requiring the C-276 to add some elements of the weld, like other nickel-base alloy or stainless steel, and these welds will be exposed to the corrosive environment, then the welding electrode or wire used to have and the parent material requires metal equivalent corrosion-resistant properties.
Hastelloy C-276 alloy solution heat treatment consists of two processes: (1) 1040 ℃ ~ 1150 ℃ heat; (2) in two minutes and rapidly cooled to the black state (400 ℃ or so), so that the material after treatment has good corrosion resistance. Therefore, only Hastelloy C-276 alloy, heat treatment of stress elimination is invalid. In the heat treatment prior to the clean alloy surface heat treatment oil and so on may be generated in the process of all carbon dirt.
C-276 alloy surface during welding or heat treatment will produce oxides, the Cr content in the alloy reduce the impact corrosion resistance, so its surface clean. You can use stainless steel wire brush or grinding wheel, then immersed in an appropriate proportion of the mixture of nitric acid and hydrofluoric acid pickling, the final rinse with water.
|
