hastelloy composition

What is the difference between Hastelloy and Stainless Steel?

Hastelloy is a nickel-based alloy, which is a difficult material to machine. The lkalloy company suggests the use of integral tools to enhance the rigidity of the tools. If the tool is made of carbide, it is inefficient. Efficiency can be improved if tempered tools with better toughness are used. For finishing, nickel or cobalt-based high-temperature alloys can be used with CBN tools. The alloys are widely used in the chemical and petrochemical industries, e.g. for chlorine-containing organic components and catalytic systems. The material is particularly suitable for high-temperature inert inorganic and organic acids (e.g. formic and acetic acid) mixed with impurities in seawater corrosive environments.

What is the difference between Hastelloy and stainless steel?

In fact, there is a clear difference between the two, Hastelloy, nickel-based alloys are usually understood as nickel-based alloys, that is, nickel has a high percentage, usually greater than 50.%, such as Monel, Hastelloy B, C series, etc., and the stainless steel is basically “steel”, so the proportion of iron is higher. For example, 304L is a stainless steel that contains more than 70% iron, although 9% nickel.

Nickel-based alloys are alloys that have high strength and a certain degree of oxidation and corrosion resistance at 650-1000°C. They are categorized into nickel-based alloys according to their main properties. According to the main properties, it is divided into nickel-based heat-resistant alloys, nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys, and nickel-based shape memory alloys. Based on the matrix, superalloys are categorized into iron-based superalloys, nickel-based superalloys, and cobalt-based superalloys. Among them, nickel-based superalloys are called nickel-based alloys.

The above is the introduction of the difference between hastelloy and stainless steel, I hope it will help you. If you want to know more about Hastelloy, high-temperature alloys, stainless steel, and other materials information, welcome to continue to close lkalloy website.

aluminum alloys heat treatment

How can we effectively prevent aluminum and aluminum alloys from producing weld heat cracks?

How to prevent aluminum and aluminum alloy welding hot cracks?

1. the selection of hot cracking tendency of small mother material, strict control of impurity content
Various aluminum alloy welding hot cracking tendency is different. One of the smaller hot cracking tendencies is industrial pure aluminum and antirust aluminum. However, in the Al-Mg alloy in rustproof aluminum when the mass fraction of Mg is 2%~3%, the tendency of hot cracking is also relatively large. Heat-treated reinforced aluminum alloys generally have a greater tendency to thermal cracking. Therefore, as a welded structure with more rust-proof aluminum, 2A16 (LY16) and Al-Zn-Mg alloy; followed by 6A02 (LD2), 2A14 (LD10), 2A11 (LY11) alloy; 2A12 (LY12), 7A04 (LC4) alloy is mainly used for resistance welding structure.

aluminum alloys heat treatment

2. the correct choice of filler metal
When the base material is determined, the correct choice of filler material is the key to preventing thermal cracking.
Generally speaking, filler metals can play a role in preventing thermal cracking from the following aspects:
① Increasing the number of low melting point eutectic, cracks plays a “self-healing” role.
For example, some hot cracking tendency of hard aluminum alloys, weld composition in the original alloy system is difficult to adjust the effect, but if ωsi5% of the Al-Si wire (SAlSi5) welding, as a result of the formation of more low-melting point eutectic, can be “self-healing”, and thus have a higher resistance to thermal cracking.
②Denaturation of the weld.
Aluminum alloy wire almost all Ti, Zr, V, B, and other trace elements, are generally added as a densification agent. These elements can form fine particles of refractory intermetallic compounds with Al and play the role of non-spontaneous crystallization core, thus refining the grain, evacuating the low melting point eutectic, and improving the weld’s resistance to thermal cracking.
③ Reduce the effective crystallization temperature interval.
For example, for welding Al-Cu-Mg system hard aluminum and the development of B61 wire to join the Ni, Mn and Ti elements, Ni and Al, Cu can be packaged crystal reaction, the formation of complex intermetallic compounds (CuAlNi), can improve the solid-phase line temperature, so that the effective crystallization temperature range is reduced, coupled with the Mn and Ti can refine the grains, and thus improve the weld’s resistance to thermal cracking.

3. the correct choice of welding methods and welding parameters
The use of heat concentration of the welding method can realize fast welding and can prevent the formation of the strong direction of the coarse columnar crystals, so you can reduce the tendency to thermal cracking, such as TIG or MIG welding tendency to warm up much smaller than gas welding.
In the choice of welding parameters, it is appropriate to choose a smaller welding current and slower welding speed. Because the current is too large not only to make the molten pool overheating, and columnar crystals coarse, and will increase the fusion ratio, so that the hot cracking tendency of the base material is too much into the weld, and thus the hot cracking tendency to increase; Welding speed is too fast, it can improve the weld in the process of crystallization of the strain rate, but also make the hot cracking tendency to increase.

Titanium alloy material

Precision machining of titanium alloy materials

As we all know, in the aerospace industry the precision machining for the material requirements is very high, of course, one side is in order to meet the special characteristics of aviation equipment, and more importantly, because of the aerospace environment impact. Because of the special environmental impact, the general materials on the market of course can not meet the needs of the environment, and are bound to need some special materials to replace them. Today to introduce you to a more commonly used material, that is, titanium alloy materials, especially in aerospace, which is more common, why is this material used more? Why is this material used more? It has something to do with its characteristics.

Titanium alloy, its specific gravity is small, determines the quality of small, high strength and thermal strength, determines the hardness and high-temperature resistance, and resistance to seawater and acid and alkali corrosion and a series of excellent physical and mechanical properties, determines that no matter what kind of environment can be used, there is also a point, the coefficient of deformation is very small, and therefore in the aerospace, aviation, shipbuilding, petroleum, chemical industry and other industries have been widely used.

Because titanium alloy materials have the above and ordinary materials are not the same place, but also decided that it is in precision machining is very difficult, many machining factories are not willing to process this material and do not know how to process this material. To this end, Xi’an Ruihua pump industry after a long period of understanding and communication with some titanium alloy processing customers, organized some small skills to share with you!

Titanium alloy material

Due to the titanium alloy deformation coefficient being small, the cutting temperature is high, the tip of the tool stress is large, machining hardening is serious, resulting in cutting processing, the tool is easy to wear, chipping, cutting processing quality is difficult to ensure. How to do cutting processing then?

In titanium alloy cutting, cutting force is not big, work hardening is not serious, easy to get a better surface finish, but titanium alloy thermal conductivity is small, cutting temperature is high, tool wear is bigger, tool durability is low, the tool should be used with titanium chemical affinity role is small, high thermal conductivity, high strength, grain size of small tungsten and cobalt class carbide tools, such as YG8, YG3 and other tools. In titanium alloy in the turning process, chip breakage is a difficult problem in processing, especially the processing of pure titanium, In order to achieve the purpose of chip breakage, the cutting part can be sharpened into a full arc of the roll chip groove, shallow before and after the depth, before and after the narrow wide, so that the chips are easy to discharge outward, so as not to let the chips entangled in the surface of the workpiece, resulting in scratches on the surface of the workpiece.

The titanium alloy cutting deformation coefficient is small, the knife and chip contact area is small, cutting temperature is high, In order to reduce the generation of cutting heat, ① the front angle of the turning tool should not be too large, the front angle of the carbide turning tool is generally taken as 5-8 degrees, due to the high hardness of titanium alloy, in order to increase the impact strength of the turning tool, the back angle of the turning tool should not be too large, generally taken as 5 °, in order to strengthen the tip of the tip of the tool part of the strength of the tool, to improve the heat dissipation conditions, and to improve the tool’s In order to strengthen the strength of the tip part, improve the heat dissipation conditions, and improve the tool’s impact resistance, a larger absolute value of the negative edge inclination angle is used.

Control of reasonable cutting speed, should not be too fast, and the use of titanium alloy special cutting fluid cooling in the process, can effectively improve the tool durability, and choose reasonable feed.

Drilling is also more commonly used, titanium alloy drilling is more difficult, often in the process of burning and broken drill phenomenon. The main reasons are poor drill sharpening, untimely chip removal, poor cooling, and poor rigidity of the processing system. Depending on the diameter of the drill bit, grind a narrow horizontal edge with a width of 0.5㎜ in order to reduce the axial force and the vibration caused by resistance. At the same time, at a distance of 5-8㎜ from the tip of the drill bit, the edge band of the drill bit should be ground narrowly, leaving 0.5㎜ or so, which is favorable for the drill bit in chip removal. The geometry must be sharpened correctly, and the two cutting edges must be kept symmetrical, so as to prevent the drill bit from cutting on one side only, and the cutting force is all concentrated on one side, which will cause the drill bit to wear out prematurely, and even cause chipping phenomenon due to slipping. Always keep the cutting edge sharp. When the cutting edge becomes blunt, stop drilling immediately and resharpen the bit. If you continue to cut forcibly with a dull bit, the bit will soon burn and anneal due to high friction temperatures, resulting in the scrapping of the bit. At the same time, the hardened layer of the workpiece will be thickened, which will increase the difficulty of re-drilling in the future and the number of times to repair and sharpen the drill bit. According to the drilling depth requirements, should try to shorten the length of the drill bit, increase the thickness of the drill core to increase the rigidity, to prevent the drilling of holes due to jitter caused by the collapse of the edge. It has been proved by practice that the length of φ15 drill bit is 150 longer than that of 195. So the selection of length is also very important.

After the above two commonly used processing to see, titanium alloy processing is also relatively difficult, but after very good processing can still be processed out of good precision parts, titanium alloy parts for aerospace equipment.

quenching layer thickness

Measurement of hardened layer thickness of steel bar quenching

After quenching the workpiece, the hardened surface layer of the organization is denser than the internal, high-frequency ultrasound through the surface coupling agent into the surface of the workpiece grain smaller martensitic organization, its energy attenuation is small; when the ultrasonic wave encounters a relatively coarse grain ferrite and pearlite, due to the difference in acoustic impedance, ultrasonic waves will be formed by the reflection of the return wave. By calculating the propagation speed and propagation time of ultrasound in this material, the distance of the echo can be obtained, and the thickness of the hardened layer can be calculated. Determination of the depth of the hardened layer on the thin surface of the steel bar parts of the detection methods is mainly microstructure measurement method, microhardness measurement method, etc… In this case, the conventional ultrasonic technology will be used, using a 20MHz high-frequency single-crystal probe for ultrasonic testing, convenient and quick.

Measurement of hardened layer thickness of steel bar quenching

The workpiece to be inspected

The workpiece to be inspected is three steel rods, the surface of the rods is a martensitic organization, and the parent material is mainly a relatively large grain ferrite and pearlite organization, as shown in Figure 1 below. the digital vernier calipers roughly measure the quenching layer of the three end faces, and the values are 4.5mm, 4.55mm, and 4.66mm respectively.

Inspection results

This testing program cleverly uses the end face echo for quenching layer thickness measurement, using a 20M high-frequency probe, and transverse wave oblique incidence detection. From the equipment side, the first higher clutter buried depth of 4.72mm can be read when detecting the No.1 end face; the first higher clutter buried depth of 4.66mm on the No.2 end face; and the first higher clutter buried depth of 4.65mm on the No.3 end face.

Test results


From the test results, it can be known that the highest wave of stray waves can be clearly seen by using a high-frequency transverse wave oblique probe. Therefore, it is feasible to use a high-frequency single-crystal probe to detect and calculate the thickness of a quench-hardening layer of certain metal steel parts.

stainless steel manufacturers

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the quality of stainless steel round steel

How to check the quality of stainless steel round steel?

How many ways to check the quality of stainless steel round steel?

Stainless steel round steel is a kind of steel section, that also belongs to the bar. Its cross-section is uniformly round, and the general length is 4 M. And the surface is smooth, without the problem of scarring. But if you want to purchase high-quality steel, then certainly still need to do a good job of measuring the quality. But how to check its quality?

the quality of stainless steel round steel

Magnetic test

After all, it is the use of stainless steel material processing, so it is still necessary to do a good job of the basic magnetic test, which is also currently confirming the quality of good stainless steel round steel is a relatively simple method. Because stainless steel is non-magnetic just, but after cold processing, there will be a certain mild magnetism.

Nitric acid point test

If it is a high-quality round steel, then one of its more important features is that it has inherent corrosion resistance to concentrated nitric acid and dilute nitric acid. This is one of the things that makes it very different from other metallic and alloy materials. If it is a high-carbon type of steel, such as 440 steel, then it may be subject to corrosion during the nitric acid point test.

Copper sulfate point test

If you want to differentiate between ordinary carbon steel and stainless steel rounds, then you can also directly utilize a copper sulfate solution to perform the spot test. It is necessary to remove all grease and contaminants from the test area before the test, then simply polish it with a soft abrasive cloth, and then go on to use the copper sulfate solution for the test. In the case of stainless steel, the surface will not produce copper deposits.

Inconel 718 alloy supplier

What exactly makes Inconel alloys so special?

What exactly makes Inconel alloys so special?

Inconel alloys are one of the most versatile metals. Due to their high performance and superior properties, their applications cover a wide range of industries. They are the natural choice for the automotive, aerospace, marine, and oil and gas industries because they are specifically optimized to withstand some of the most demanding manufacturing conditions.

Inconel 718 alloy supplier

What is it about Inconel that makes it so special? Here’s everything you need to know about them.

1. How Inconel Alloys are Made

Although Inconel alloys vary widely in their composition, they all have nickel and chromium as their primary elements. These specialty metals are not to be confused with duplex stainless steel, austenitic stainless steel, or any other type of stainless steel alloy. The different types of Inconel® alloys and their respective compositions are briefly described here.


This nickel-chromium alloy is highly resistant to a wide range of corrosive elements. It will not succumb to general oxidation or stress corrosion cracking caused by chloride ions, even under extreme temperature conditions.


Inconel 601 contains nickel, chromium, and aluminum. The addition of aluminum gives it excellent mechanical properties even in high-temperature environments.


Inconel 625 contains nickel, chromium, molybdenum, and niobium. The reaction between molybdenum and niobium results in hardening of the matrix microstructure of the alloy, which increases its overall tensile strength. It is this nickel-based alloy that is extremely resistant to common corrosive elements under harsh conditions.


Unlike the other metal alloys in this series, Inconel 690 is made from high chromium and nickel. The use of high chromium makes this particular metal alloy variant highly resistant to corrosive conditions synonymous with aqueous environments. Its high corrosion resistance also allows it to withstand vulcanization that occurs in high-temperature environments.

Inconel 718 alloy supplier

The structure and response of Inconel 718 are quite different from the other metals in the series. This nickel-based high-temperature alloy is made from nickel and chromium, as well as significant amounts of molybdenum, niobium, and iron. It also contains trace amounts of aluminum and titanium. The combination of these alloying elements makes Inconel 718 very strong, flexible, and resistant to post-weld cracking.

2. Applications for Inconel alloys

Manufacturers and design engineers use Inconel alloys in a number of industrial applications that require reliable and technically superior materials. The fact that they have excellent corrosion and high-temperature resistance makes them very attractive.

These alloys are best reserved for use in environments that other materials cannot withstand. Here is an overview of some of the major industrial applications that rely on Inconel alloys.

Aerospace Industry

Jet engine components are consistently exposed to high pressures and temperatures. As a result, the materials used in their construction need to withstand these conditions while maintaining their strength and integrity.

Nickel-based high-temperature alloys are the natural choice for any high-temperature application. It offers corrosion resistance in high-stress environments, creep deformation resistance, and low expansion even at high temperatures. For example, Inconel 718 and 750 are used to make turbine seals, fasteners, and exhaust bushings.

Automotive Industry

An automobile engine is a sophisticated piece of machinery. It generates a lot of heat, but still needs to be efficient, lightweight, and reliable. Inconel 600, 601, and 625 have a wide range of applications, including the manufacture of key components for high-performance vehicles. In addition, it is commonly used in passive safety devices such as airbags, electrical switchgear, fuel pumps, sensors, ignition systems, and exhaust fittings.

Marine Industry

Inconel alloys deliver high performance even under the most extreme conditions, such as in the marine industry. Nickel alloys are manufactured to withstand the highly corrosive conditions of offshore processing plants that rely on seawater as a coolant.

Inconel 625 is widely used in submarine communication cable sheathing, propulsion motors, propeller blades, wire ropes, and even downhole equipment.

3. Characteristics of Inconel alloys

One of the most notable characteristics of Inconel alloys is their corrosion resistance. They also have significant oxidation resistance and can withstand high temperatures even when compared to stainless steel.

When exposed to high temperatures, Inconel forms a protective passivated oxide layer on its surface to protect it from further damage. Not only is it heat resistant, but it maintains its strength under these conditions. In addition, Inconel is resistant to pressure, making it ideal for extreme applications in a variety of fields.

What performance characteristics does seamless pipe possess?

A seamless pipe is a kind of cylinder made of round steel, which is drawn directly from the billet. Seamless pipe is a little stronger than straight seam steel pipe, and can produce steel pipe with larger diameters from a narrower billet, and can also produce steel pipe with different diameters from the same width of billet. Share with you what performance characteristics seamless pipe has.

Performance characteristics of seamless pipe

Seamless pipe performance characteristics:

1) Seamless steel pipe is actually a hollow steel pipe with a certain cross-section and no seams. Seamless steel pipe is a kind of steel pipe processed from steel by piercing, cold rolled, or cold drawn and processed into a pipe.

Because the pipe is hollow inside, it can transport some fluid liquids, in addition to the traditional solid steel, compressive strength is greater, and the volume is light, a more ideal type of economic steel pipe. It is widely used in manufacturing and processing industries, such as oil drilling rods, vehicle frames, and scaffolding for construction.

2) At the same time, seamless steel pipe can also be processed into ring-shaped parts, the full use of materials, simplifies the production process, greatly reducing the production cycle. At the same time, steel tubes also play a significant role in the manufacture of some weapons, such as gun barrels need to use steel tubes for manufacturing.

Seamless steel pipe can be divided into two categories according to its hollow cross-section: round and profiled. When the perimeter of the two products is the same, the round pipe conveys a larger amount of fluid and the force inside the pipe is uniform. However, round steel pipe is not as good as shaped steel pipe in terms of bending, so it is used in different fields of application for different steel pipe performance characteristics.

About the introduction of the performance characteristics of seamless pipe, today we share with you here, we will see you in the next issue!

Seamless steel pipe hardness

Seamless steel pipe hardness testing method

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.

Seamless steel pipe supplier

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.

316 stainless steel supplier

Is there a way to identify 316 stainless steel?

Steel material 304 and 316 identification methods are as follows:

Identification of color and luster

After pickling of stainless steel, the surface color and lustre silver white and clean: chromium-nickel stainless steel color silver white jade; chromium stainless steel color white slightly gray luster is weak; chromium-manganese-nitrogen stainless steel color and chromium-nickel stainless steel is similar to the color and lustre is slightly lighter. The surface color of the stainless steel without pickling: chromium-nickel steel is brownish white, chromium steel is brownish black, and chromium manganese nitrogen is black (these three colors refer to the oxidation of the heavier color). Cold rolled unannealed chromium-nickel stainless steel, the surface of silver-white reflective.

Identification with a magnet

Magnets can basically distinguish between the two types of stainless steel. Because chromium stainless steel in any state can be attracted by magnets; chromium-nickel stainless steel in the annealed state is generally non-magnetic, in the cold-worked, some will be magnetic. However, high manganese steel containing high manganese is non-magnetic; the chromium-nickel-nitrogen stainless steel magnetic situation is more complex: some are non-magnetic, some magnetic, and some longitudinal surface is a non-magnetic and magnetic cross-section. Therefore, although the magnet can basically distinguish chromium stainless steel and chromium-nickel stainless steel, but can not correctly distinguish some of the special properties of the steel, and also can not distinguish the specific steel number.

316 stainless steel supplier

Identification with copper sulfate

Will remove the oxide layer on the steel, put a drop of water, with copper sulfate rub, rub, such as no color change, generally for stainless steel; such as purple red, non-magnetic for high manganese steel, magnetic generally for ordinary steel or low alloy steel.

For special properties of steel, we also need to take the following three ways to identify.

Abrasive identification

Grinding flower identification is the stainless steel in the grinder, view its sparks. If the spark is streamlined, and there are more dense knots, that is, high manganese-containing high manganese steel or manganese-nitrogen steel; such as no knots that is chromium steel or chromium-nickel stainless steel.

Annealing method of identification

Cold working chromium-nickel stainless steel, such as magnetic, can take a small piece of red in the fire to let it cool naturally or into the water (annealing), generally speaking, after annealing the magnetic properties will be significantly weakened or completely disappeared. But some chromium-nickel stainless steel, such as Cr18Ni11Si4AlTi steel and Cr21Ni5Ti steel, because the steel contains more ferrite elements, and its internal organization has a considerable part of ferrite. Therefore, even in the state of hot working, there are magnetic.

Chemical characterization method

The chemical characterization method is to identify the magnetic stainless steel containing nickel is an identification method. The method is to dissolve a small piece of stainless steel in aqua regia, use clean water to dilute the acid, add ammonia neutralization, and then gently injected it into the nickel reagent. If there is a red fluffy material floating on the liquid surface, that is, indicating that the stainless steel contains nickel; if there is no red fluffy material, that is, to prove that the stainless steel is without nickel.