Seamless tube manufacturing process- know about all process in brief

In this article, you will learn about the manufacturing of seamless tube manufacturing. The introduction of the advance rolling mill technology and its growth during the first 19th century also placed in the tube manufacturing industries. Toward the end of the century, different types of process are available for manufacturing of seamless tubes, hence the production process became available for the manufacturers. The production volume of tubes has increased due to its vast demand in the industrial and engineering sectors.

Below are some manufacturing processes of seamless tubes:

1# mandrel mill process

In this type of manufacturing process, a steel billet is heated and pushed to a forging process in the rotary furnace. It is induced in the cylindrical hollow which is also known as mother hollow. this is produced from the help of rotary piercer. The set of roller arrangement keeps piercer at the center of the steel billet. The OD is same approx that of the inside diameter of the finished tube. Due to the secondary roller arrangements outside diameters and thickness are achieved. In order to maintain temperatures, tubes are processed for reheating furnace that increases the temperature of the tubes.

2# forging process to manufacture seamless tube manufacturing:

In a Forging operation, a billet is heated and placed in forging die that has a somewhat larger diameter than a finished tube.  The hydraulic press has a forging hammer have the same inside diameter of the tube that is used to create cylindrical forging. After the forging operation, it is machined to achieve the desired dimension. Generally, the forging operation is used to produce large diameter stainless steel 304 seamless tubes that cannot be manufactured using standard operations. The forged tubes are used for high heating applications.

3# Extrusion operation for seamless tube manufacturing process:

It is the same as the forging operation, the heated billet is placed between the die. The hydraulic ram pushes the steel billet against the piercing mandrel. Hence, the billet passed from the cylindrical cavity between die and mandrel. This operation produces the billet to the tube. In some cases, tubes manufactured with a high thickness which is known as mother hollow cavity. Many manufacturers used the mother hollow to manufacture tube with the different dimension with extrusion operations.

4# Plug mill process:

This process was invented by German engineer Mannesmann. The main difference between a mandrel and plug mill process is that in mandrel process used to achieve the inside diameters. On the other hand, by plug mill process multi-stage reduction is possible. So the greater thickness reduction is achieved. In this process, the heat treatment process is performed.

The manufacturing material is processed from different heat treatment process such as normalizing, quenching, tempering, solution Annealing, stress relieving, and other combination of the heat treatment process. The finished tubes are processed from various quality test stages for quality assurance. Those tests include a hardness test, leakage test, compression test, mechanical test, PMI test, radiographic test, and IGC test. Other tests are pitting corrosion test, destructive test, ultrasonic test and more.

This is all about the manufacturing of seamless tubes.

Know about nickel Alloys and its resistance to corrosive environments

In 1751, the nickel (Ni) was discovered in Stockholm, Sweden by A.F Cronstedt and added to the periodic table. Nickel is a silver whitish metal that is found on sulfide and arsenic ores. It is derived by roasting to NiO and reducing the carbon elements. Carbonyl process is used to manufacture pure nickel grade. On the other hand, the impure nickel grade reacts with carbon monoxide to form Ni (CO) 4. This is subsequently decomposed at 200 deg C to succumb nickel alloy.

The pure nickel grade has resistance to corrosion in water or air. Thus, it is used as a protective coating. The nickel grade is malleable, ductile and readily soluble in dilute acids, however, the alkalis will not affect it.

The nickel grades are widely used, ranging from industrial to engineering applications. Mainly, the nickel grade is used as a constituent of different types of alloys. Additionally, these are utilized as a protective coating in the food and chemical processing industries. It is known as a carcinogen. Nickel is also an allergen to certain individuals. However, it is a part of many dietetic constituents, and hence cannot be removed easily.

The brief description of nickel alloy:

It is a commercially pure (CP) grade having the properties that are ideal for several fields, mainly in chemical processing and electronics applications. It has great resistance to many reducing chemicals and is matchless resistance to caustic alkalies. The commercially pure nickel has high thermal and electrical conductivity. The nickel alloys have higher core temperatures and also possess good magnetostrictive properties. In the annealed condition the nickel grade has a low hardness and good ductility and malleability. These properties are joined with great readability makes it highly fabricable.

Nickel Alloy is divided into 2 grade 200 and 201. Nickel alloy 200 Round Bars has a relatively low work hardening rate; however, it can be cold worked to achieve moderately high strength and maintains ductility. The nickel alloys have good mechanical properties and outstanding resistance to many corrosive environments. Some other salient features of an alloy are its magnetic properties, low gas content, low vapor pressure, and more.

The corrosion resistance of nickel alloys makes it particularly useful for maintaining product purity in the handling of synthetic fibers, and other demanding media. These are used in the structural applications where corrosion resistance is the prime issue.

The nickel alloy is considered as the superalloy due to its features offers to any application. These are easily alloyed with any types of alloying elements and enhance their properties. The nickel alloys offer great resistance to pitting and crevice corrosion cracking in the environments that contain warm chlorides. These can be exposed to elevated temperatures without any elongation and distortion.

The nickel grade offer service in the exposure of harsh chemicals such as nitric acids, sulfuric acids, phosphoric acids, and other harsh acids. Advantageously, these are inherent to the application in organic and inorganic compounds. In the mild cyclic environments, nickel alloys offer service while retaining its structure and offering less erosion. These are well suited for the chromium carbide precipitation range.

Types of steel pipes and uses in piping industries

 Since the manufacturing process has greatly changed and has become more complex. The industries are involved in producing a variety of ranges of pipes that suits the demands and requirement of the clients. There are many types and range of steel pipes available in the market that is offered by the companies.  All these types of steel pipes have different features and properties that make it useful as per its suitability.

Talking about the steel alloy, these consider carbon and iron including with a small percentage of other metals like aluminium, chromium, and nickel. Combining with other elements these steel pipes forms other ranges and types. Here are the types of steel pipes mention below-

Carbon Steel Pipes – These are a range of steel pipes that are designed from the proportion of carbon content adding up with iron content.  Similarly, carbon steel exhibits superior resistance to corrosion and durability. Apart from these are further categorized into four types based on the amount of carbon included in the alloy. These are low carbon steel, medium carbon steel, high carbon steel, and very high carbon steel. These pipes are extensively used in many industries basically in oil, gas transmission, automobiles, etc.  This pipe holds superb workability, ductility, strength and is safe to use.

Alloy Steel Pipes– By its name it suggests that these pipes are formed with a specified amount of other elements. The major alloying element, it includes is manganese, chromium, nickel, titanium, aluminium, and copper. This alloy steel pipe is considered a workhorse of many industries due to its extensive availability, inexpensive cost, and ease of processing.  Due to its exceptional performance properties, these are used in oil refineries, power generations, petrochemicals, chemical plants and in sugar mills. The addition of elements imparts superior corrosion resistance to pipes. Furthermore, it possesses good strength, ductility, mechanical properties and durability that enable to withstand in high-temperature circumstances.

Stainless Steel Pipes- These steel pipes have belonged to the family of steel that generally comprises 10 to 30% of chromium in addition to low carbon content. Furthermore, these include molybdenum, titanium, copper, nitrogen, aluminium and nickel content. This addition of content imparts superior useful properties that enhance superior resistance to corrosion and formability.  Therefore on the surface of the steel, the presence of chromium content creates a thin layer of the oxide that is known as the passive layer that provides great prevention from further corrosion.

These stainless steel 321H pipes exhibit superior resistance to crevice and stress corrosion cracking in elevated temperatures. To increase impact resistance and strength of the pipes these are properly heat treated. These pipes are used in various industrial applications such as pharmaceutical, oil and gas applications,  food production and in power generations.

 The manufacturing of these ranges of steel pipe is done with the use of high quality of raw material and with highly advanced machinery. These are the most common types and range that is utilized worldwide and are highly appreciable by the clients.

Temperature range of Stainless Steel 304 Vs 316

Stainless steel has good strength and good corrosion resistance ability in higher temperature environments. The most searched SS grade is 304 and 316, due to the prominent features it offers to the applications. These grades are extensively used in many application ranges from moderate temperatures to high temperatures such as superheaters, heat exchangers, valves and other heating applications. However, their heat capacities differ from each other that vary its properties.

Temperature range of 304 grades:

SS 304 grade is from the 300 series of austenitic stainless steel modified with controlled carbon chemistry for increased strength up to 1500 deg F. UNS S30400 is a unified numbering system of 304 grades. Generally, it is the modified version of 18/8 chromium and nickel base austenitic alloy. The carbon content present on it about 0.04 % to 10 % that increases its strength above 800 deg F. It is the most cost-effective and versatile alloy suitable for a wide range of applications.

Stainless Steel 304 Tubes has good resistance to atmospheric corrosion and many organic and inorganic compounds in moderately oxidizing to severe reducing conditions. It has the highest chromium content that provides resistance to oxidizing agents such as nitric acids up to 176 deg F temperature.

This grade also opposes harsh organic acids like acetic acids. In addition to the nickel, it offers resistance to moderate reducing solutions like phosphoric acids even in the higher concentration too. This grade can offer service in caustic solutions free of chlorides at nominal temperatures.

The hot working temperature of this grade is between 1652 deg F to 2102 deg F, the same temperature is recommended for the hot working process. In order to acquire maximum corrosion resistance, this grade is subject to the annealing process and quenched with water.

A higher concentration of chlorides, it is susceptible to pitting and crevice corrosion. The high molybdenum content is needed for the successful performance in the most severe conditions.  

Temperature range of 316 grades:

Alloy 316 (UNS S31600) /S31603) is chromium, nickel, and molybdenum austenitic stainless steel. It is designed for improved corrosion resistance in the high temperatures. These are often utilized in the process streams that contain halides and chlorides. In addition to molybdenum, its resistance ability to corrosion and pitting is enhanced. 316 grades provide excellent properties such as stress to rupture strength and tensile strength even in the hoisted temperatures. This grade is weldable with more standard techniques.

These are not corroded in process streams. SS 316 performs well in sulfur-containing environments such as that encountered in industries. This alloy can be utilized in higher concentrations at temperatures up to 120 deg F.

The working temperatures of this alloy are ranging from 1700 deg F to 2200 deg F. These are also subject to the hot working process at the same temperatures. The annealing process is performed at 1900 deg F to acquire higher corrosion resistance. These are also quenched with water.

So, these are the temperature ranges of stainless steel 304 and 316. Choose one as per your application suitability.