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What are the seamless steel pipe hardness testing methods?

The hardness test of stainless steel should take into account its mechanical properties, which are related to the performance and quality of deformation, stamping, cutting, and other processing carried out with stainless steel as raw material. Therefore, all seamless steel pipes should be tested for mechanical properties. Mechanical properties test methods are mainly divided into two categories, one is the tensile test, and the other is the hardness test.

The tensile test is a seamless steel pipe made of specimens, in the tensile testing machine will be pulled to break the specimen, and then determine one or several mechanical properties, usually only determining the tensile strength, yield strength, elongation, and section shrinkage. The tensile test is the most basic mechanical properties of the metal materials test method, almost all metal materials, as long as the mechanical properties of the requirements, are specified tensile test. Especially for those materials whose shapes are not convenient for hardness tests, the tensile test becomes the only means of mechanical property inspection.

A hardness test is a rigid indenter according to the specified conditions slowly pressed into the surface of the specimen, and then testing the depth or size of the indentation, in order to determine the size of the material hardness. The hardness test is the simplest, quickest, and easiest to implement method in the mechanical property test of materials. The hardness test is non-destructive, with material hardness value and tensile strength value between the approximate conversion relationship. The fact that the hardness value of a material can be converted to a tensile strength value is of great practical significance.

Since the tensile test is not easy to test and it is convenient to convert from hardness to strength, people are increasingly testing only the hardness of the material and less often its strength. Especially due to the continuous progress and innovation of hardness tester manufacturing technology, some of the original can not directly test the hardness of the material, such as seamless steel tubes, stainless steel plates, and stainless steel strips, etc., are now possible to directly test the hardness. Therefore, there is a hardness test that gradually replaces the trend of the tensile test.

Most of the national standards in stainless steel materials are simultaneously specified in the tensile test and hardness test. For those materials that do not facilitate the hardness test, such as seamless steel pipe only provide for the tensile test. The stainless steel standard generally provides for cloth, Luo, dimensional three hardness test methods, determination of HB, HRB (or HRC), and HV hardness value, the provisions of the three hardness values can be measured only one of them.

Seamless steel pipe inside diameter of 6.0mm or more, a wall thickness of 13mm below the annealed seamless steel pipe, you can use a W-B75 type Wechsler hardness tester, which test is very fast, easy, and suitable for seamless steel pipe to do a quick and non-destructive qualification test. Seamless steel pipe inner diameter greater than 30mm, wall thickness greater than 1.2mm seamless steel pipe, using Rockwell hardness tester, test HRB, HRC hardness. Seamless steel pipe with an internal diameter greater than 30mm, wall thickness less than 1.2mm seamless steel pipe, using surface Rockwell hardness tester, test HRT or HRN hardness. Seamless steel pipe with inner diameter less than 0mm and greater than 4.8mm, use Rockwell hardness tester for pipe, test HR15T hardness. When the inner diameter of a seamless steel pipe is greater than 26mm, you can also use Rockwell or a surface Rockwell hardness tester to test the hardness of the inner wall of the pipe.

In this article we will take a closer look at the material characteristics and what wire is used to weld inconel600. Like all nickel alloys, inconel600 has excellent corrosion resistance and a range of other chemical properties that make it suitable for the harshest and most demanding environments. Due to inconel600’s excellent properties, ease of fabrication, and wide range of forms, it plays an important role in many different industries and applications.

Application areas for inconel600 high-temperature alloy are rotating and stationary parts for highly stressed gas turbines and rocket engines, high-pressure bolts, springs and fasteners, nuclear reactor and spacecraft components, extrusion or shearing (e.g. copper), it is also used in very important applications such as pump shafts used in offshore and marine engineering, other highly stressed wellhead equipment and oil well equipment. inconel600 The standard product forms of the high-temperature alloy include sheet, bar, plate, round bar, flat bar, forged buttstock, hexagonal, and wire in sizes that each have a variety of uses, which means that it has a variety of uses, and is also easy to fabricate through all of the standard procedures for nickel-based alloys.

inconel600 high-temperature alloy chemical composition:
Carbon (C) ≤ 0.30,
Nickel (Ni) ≥ 63.0,
Silicon (Si) ≤ 0.5,
Sulfur (S) ≤ 0.024.
Iron(Fe) ≤2.5, Manganese(Al) ≤0.5
Manganese(Al) ≤2.0, Copper(Cu) ≤2.5
Copper (Cu) 28.0 ~ 34.0
Physical Properties: Density: 8.9g/cm3.
Melting point: 1300-1350 ℃.
Magnetic properties: None

Finally, each grade of inconel600 high-temperature alloy offers specifications and properties that enable design engineers to select the right material for each job. each grade develops over time, creating new versions that are enhanced or evolved in some way to offer different properties. inconel600 high-temperature alloy is available in both C-type and G-type from a corrosion standpoint. Many of the properties of the HASTELLOY materials, notably resistance to chloride pitting and crevice corrosion, and resistance to abrasion and aqueous corrosion Cobalt alloys perform similarly to STELLITE alloys with lower carbon content from a wear perspective.

Incoloy 800H Welding For 800 H/HT use below 787°C, and weld with wire 82 (ER NiCr-3). R A 330-04 (N08334) wire has a matching coefficient of thermal expansion and higher strength. If maximum mechanical strength is desired, it is best to use wire 617 (ERNiCrCoMo-1) or electrode 117 (ENiCrCoMo-1).

In order to avoid cracking at grain boundaries due to stress relaxation that may occur in 800H/HT welded parts above 538°C, a post-weld heat treatment is required at 899°C, with a holding time of one hour for every 25 mm of material thickness (at least half an hour/25 mm of thickness), followed by air-cooling.

The corrosion resistance of Incoloy 800H.

800H is resistant to many corrosive media. Its high nickel content gives it good resistance to stress corrosion cracking in aqueous corrosive conditions. The high chromium content gives it better resistance to pitting and crevice corrosion cracking. The alloy has good resistance to nitric and organic acid corrosion, but limited resistance to sulphuric and hydrochloric acids. There is good corrosion resistance in oxidizing and non-oxidizing salts, except in halides where pitting corrosion is possible. It also has good corrosion resistance in water, vapor, and mixtures of steam, air, and carbon dioxide.

Strengthening Mechanism of Incoloy800H Alloy

In order to achieve excellent corrosion resistance and mechanical properties of Incoloy 800H alloys, it is necessary to add a variety of alloying elements to improve the corrosion resistance of the alloy and strengthen the austenite matrix.

Solid Solution Strengthening

Solid solution strengthening of Incoloy800H alloy is to add Fe, Cr, and other alloying elements to the matrix to form single-phase austenite, and the atomic radius of these elements is different from that of Ni, which produces an aberrant stress field within the crystal, hindering the movement of dislocations, thereby increasing the strength of the alloy. Because Ni and Fe, Cr, and other elements can form an infinite solid solution, the austenite matrix can be solidly dissolved into a large number of Fe, and Cr elements without phase transition.

Precipitation strengthening

Precipitation strengthening in Incoloy800H alloy plays an important role, γ ‘phase is an important strengthening phase in Incoloy800H alloy, for the FCC structure, and the matrix is a co-grid relationship. In practice, Ti atoms in the γ’ phase often replace some of the Al atoms to form Ni3(Al, Ti) reinforced phase. Due to the low interfacial energy between this phase and the austenitic matrix, the γ’-strengthened phase usually maintains high organizational stability [26]. In addition, the γ’ phase is able to strengthen the austenitic matrix through its interaction with the dislocation motion of the Al and Ti contents and the effect of the solid solution treatment on the organization and properties of Incoloy800H alloys (bypassing and cutting particle mechanisms), while the inherent plasticity of the γ’ phase avoids the second phase from acting as a source of crack initiation.

What are the properties of INCONEL alloy C276?

Nickel alloys need to work hard in extreme environments containing corrosive acids and other aggressive media. Even under the harshest conditions, INCONEL alloy C-276 is a popular choice. Here, we look at its properties and why they are suitable for these harsh environments.

There are many factors to consider when choosing the right material for harsh industrial environments. You need to know what kind of corrosive media will be present, what the operating temperature range is, and what loads the material will be subjected to. In a harsh situation, the material will need to be able to operate in some of the most corrosive conditions on earth, at high temperatures and high pressures.

Finding an alloy that can survive in such extreme environments is not an easy task. INCONEL C-276 alloy is a material worth considering due to its excellent corrosion resistance to a wide range of aggressive media. It is widely used in a variety of different industrial applications and is considered to be one of the most versatile options available in harsh environments. As a supplier of nickel alloys, Shanghai Makan Alloys has a comprehensive understanding of each material and a wealth of experience in the properties, characteristics, and applications of this technologically leading alloy.

1. Alloy C276 Main Characteristics
INCONEL Alloy C-276 is used in harsh environments due to its nickel alloy properties. It is a nickel-chromium superalloy with a high molybdenum content (15-17%). It is also possible to control the tungsten and iron content and to strictly limit the carbon content. The low carbon content minimizes carbide precipitation during heat treatment and welding. This means that the alloy retains its excellent resistance to pitting and crevice corrosion when used in welded structures. In other materials, the weld zone is weakened by heat during the welding process and is, therefore more resistant to corrosion.INCONEL alloy C-276 is sometimes covered with lower alloyed materials in the weld zone to provide additional protection and even higher performance in industrial applications.

The material’s corrosion resistance is one of its main highlights. Even in very harsh environments, it resists general corrosion such as stress corrosion cracking, pitting, and crevice corrosion very well. It is also extremely resistant to sulfuric, hydrochloric, and phosphoric acids. Highly oxidizing, neutral, and acidic chlorides; as well as solvents, formic and acetic acid, acetic anhydride, wet chlorine gas, hypochlorite, and chlorine solutions. This is what makes it so well used in the chemical processing industry. Finally, it also has excellent resistance to seawater corrosion, especially in crevice conditions.

2. Alloy C276 industry applications

With such a wide range of resistance, it is no wonder that INCONEL alloy C-276 is used in many industrial applications.

For example, it is used in flue gas desulfurization (FGD) systems to control air pollution in power plants. Components it is used in include scrubbers, piping, and stack liners. Compared to other alloys, INCONEL C-276 alloy has the ability to withstand higher chloride content before localized corrosion occurs. Given the presence of chlorides in scrubber liquids and gas condensates, this is certainly the preferred choice in this industry.

This nickel alloy has also been chosen for certain oilfield and subsea applications. When recovering and processing sour natural gas, which often contains hydrogen sulfide, carbon dioxide, and chlorides, the material needs to have good resistance to sulfide stress cracking and stress corrosion cracking. INCONEL alloy C-276 has high levels of nickel, chromium, and molybdenum, which together can provide this resistance even at high temperatures in deep wells. It’s used in things like piping, downhole, and surface components.

Its composition is also used for pollution control and waste treatment in very harsh environments. The high molybdenum content of INCONEL alloy C-276 helps create resistance to pitting and crevice corrosion. It is used in the most aggressive portions of waste liquid handling systems where other materials will not be able to cope with harsh conditions. In air pollution control, the alloy is used in stack linings, ducts, dampers, scrubber towers, stack gas reheaters, fans, and fan shrouds.

INCONEL alloy C-276 is also an important material in chemical processing. It has been selected for use in processes containing ferric and copper chloride ions, chlorine, hypochlorite, chlorine dioxide, organic acids, acetic anhydride, seawater, brine, and acidic oil and gas wellhead fluids. It is used in heat exchangers, reaction vessels, evaporators, and transportation piping.