Technology for manufacturing shells made of sheet steel

Basic terminology, the essence of rolling

First you need to understand the basic concepts that are used in such a field of activity as the manufacture of shells.

Rolling is a method of processing metal blanks using high pressure. As a result, the shape of the part changes, with a uniform distribution along the length. Without this stage it is impossible to imagine the creation of a large number of parts.
The operation is carried out using a rolling tool. Other details received the name rolls.
After the operation is completed, finished parts or blanks appear, then undergo additional stamping. And they are delivered, for example, to Obninsk.

Shells, the production of which is not so difficult to organize, are a structural element of a cylindrical or conical shape. Performed using several forms:

Metal rolling technology

The feed of the workpiece during sheet bending on rollers can be longitudinal, transverse or helical (also called spiral).
The longitudinal method is used to produce long-length pipes; the transverse method produces short ones. Spiral feeding produces pipes that do not need to be sealed by welding. For sheets of small thickness, up to 6 mm, roller bending is performed using the cold method. For thicker and non-plastic workpieces (for example, on a titanium base), heating in an oven to a maximum of 300 degrees is used.

Features of defects, description of technology

When rolling, work is carried out with the sheet folded or without performing this operation, it all depends on the geometric dimensions of the part and the initial strength indicators. When choosing equipment, these parameters play an equally important role. When manufactured, the shells can have the following dimensions:

Thickness ranges from 3 to 100 mm.
Length – 30-3100 mm.
The diameter of the outer side is 20-280 centimeters.

When deforming inside metal parts, distortions reach extreme values. The thickness also changes.

The operation itself for rolling structures made of metal and stainless steel consists of two main stages - bending, and the rolling itself. The last part of the process is distinguished by the fact that it promotes the movement of bending over the entire surface being processed.

Internal stresses may arise in the metal after metal rolling is completed. There are three types of such phenomena. They are also taken into account by those who work in the city of Obninsk.

Zonal stresses appear between individual sections of the section and parts of the part. It is this deformation that most contributes to the appearance of defects, which is why it is considered the most dangerous. Afterwards, warping and cracks appear on the surface of the rolls and other parts. Their properties depend on the temperature gradient that appears between different parts of the part during temperature exposure. mm is also used for measurement.
Changes in the structural type occur in grains either inside or outside. The appearance of stress is associated with different expansion coefficients with different characteristics. The formation of new phases of different volumes can also lead to additional items. This negatively affects the production of rolled and other types of parts. Obninsk is no exception.
Voltages of the third group appear inside the volume of several cells that make up the crystal lattices. This can make hemming the edges more difficult.

All voltages have a different nature of formation. But the consequences remain the same - the occurrence of elastic deformation, distortion inside the crystal lattice. But this does not affect the production of packaging for thick-walled products, for example.

Problems can be easily eliminated; it is enough to use heat treatment. After all, the very nature of the deformations changes if they are greatly cooled or heated. For example, as temperatures rise, the surface layers expand. But the core remains unheated, creating additional obstacles. This also applies to edges.

This leads to the appearance of compressive stress. The 24 mm shell is no exception. But cooling makes the processes happen in reverse order. The surface layers usually have a lower temperature.

That is why they are subject to stress more than those layers that are deeper. But after final cooling, the temperature will be equalized over the entire surface of the metal. Flaring is not needed. But additional customization never hurts.

However, you should not expect that the defects will be completely eliminated. There are also stresses that are called residual. Those who need to carry out edge processing are also familiar with them.

Heat treatment, such as tempering, has other beneficial properties for corner products. Those who work with hardened steel may need this operation.

Prices for stainless steel shells

Du, mm	Wall thickness, mm	price, rub. (cost per ton)
		Art. 12Х18Н10Т
		Customer's material	Supplier material
325–1820	from 8 to 16	110000	350000
325–1820	from 16 to 30	145000	440000

Production of stainless steel shells

Our company produces stainless steel shells made of 12x18n10t steel. Rolled metal is resistant to corrosion, pressure drops and critical temperatures. The fittings are suitable for any climatic conditions. Stainless steel shell pipes are used in pipelines with an aggressive working environment. Fields of operation: chemical, food, energy industries.

The technology for manufacturing stainless elements does not differ from the production of shells made of carbon or alloy steel. A sheet of metal is placed between the shafts of a rolling machine and bent under pressure into a pipe of the required diameter. The edges of the workpiece are connected with a longitudinal weld. To achieve precise relationships between diameter and wall thickness, the part is calibrated. The strength of permanent connections is checked using ultrasound. Weldability is increased by mechanical and heat treatment.

The price of elements made of steel 12x18n10t is influenced by the quality of the rolled product, the amount of consumables and the degree of processing. You can buy stainless shells and arrange delivery by phone or email.

Characteristics

Temperature conditions when working with non-aggressive media: from -196°C to +600°C; under corrosion conditions: up to +350°C.
Steel class: structural cryogenic.
Chemical composition: 67% iron; 0.12% carbon; 17-19% chromium; 9-11% nickel.
Connection method: electric arc welding.
Wall thickness: from 8 to 30 mm.
Nominal diameter: 325-1820 mm.
Working substances: corrosive liquids, gases.
Type: cylindrical, conical.
Dimensions are specified separately.

Delivery conditions

Price, product availability, conditions and guarantees

We work with both legal entities and individuals. We are ready to supply products to order.

We have a cumulative discount system for regular customers.
Terms of payment
You can pay for your order in 3 ways: cash, bank transfer, bank card.

We provide deferred payment for up to 1 month to regular and well-established clients.

Options: order from us, use the services of a transport company, arrange pickup.

For any type of payment, we ship the goods the next day after receipt of payment.

Reception and unloading of goods

You must ensure unimpeded access for our vehicles to the unloading site.

Upon unloading, you receive a package of documents: waybill, invoice and quality certificate (on request).

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Why are shells so necessary?

These details become the main ones when building buildings. Among the units of the unit, this one is characterized by its material consumption and the greatest responsibility. That is, it takes on the maximum load. When laying process pipelines, you can’t do without this design at all, just like you can’t do without rolls.

Column equipment and pipelines of non-standard shapes are made from shells. Each product is accompanied by a document.

In mechanical engineering, production is also impossible to imagine without such parts. Many structures that have a conical or round shape can be called shells. The main thing is to contact the manufacturer, who guarantees full control of production processes and compliance with the required dimensions.

Source

Basic terminology, the essence of rolling

First you need to understand the basic concepts that are used in such a field of activity as the manufacture of shells.

Rolling is a method of processing metal blanks using high pressure. As a result, the shape of the part changes, with a uniform distribution along the length. Without this stage it is impossible to imagine the creation of a large number of parts.
The operation is carried out using a rolling tool. Other details received the name rolls.
After the operation is completed, finished parts or blanks appear, then undergo additional stamping. And they are delivered, for example, to Obninsk.

Shells, the production of which is not so difficult to organize, are a structural element of a cylindrical or conical shape. Performed using several forms:

Sheet steel shells are elements that become irreplaceable parts of tanks and tanks, boilers, and other similar metal structures. Non-ferrous and ferrous metals and their alloys are becoming the main materials in production. Obninsk is no exception.

Stages of shell manufacturing

Kaluga Experimental Mechanical Plant LLC is engaged in the manufacture of conical shells (as well as cylindrical shapes) in standard and non-standard sizes. The production is equipped with high-precision equipment, including Italian and German sheet bending machines. Finished products are of high quality and reliability.

The shell manufacturing process takes place in stages:

Purchase of materials, taking into account the thickness, dimensions, characteristics of the part that is planned to be manufactured.
Cut out the shapes according to pre-calibrated dimensions.
Rolling of shells. On sheet bending machines, a pipe (or pipes) of the desired shape is formed from metal sheets;
Welding. The next step is to weld the edges longitudinally and transversely, the seam is sealed and reliable;
Checking products for compliance with specified geometric parameters;
Checking seams. Specialists test welding seams for strength and tightness. The most popular control method is ultrasonic;
Delivery to the customer in a convenient way.

Manufacturing of shells

The shell is a cylindrical or conical part that is not plugged at the ends (i.e., without a bottom). In cross section, the part looks like a ring.

Where can shells be used?

Shells are used in mechanical engineering (nozzles, transition rings from one pipe thickness to another, conical transitions from one diameter to another), as an element of the body of steam boilers and high-pressure cylinders, as well as in the manufacture of non-standard pipelines. In addition, shells are used in the design of tanks for storing bulk materials and in transport for transporting liquid and gaseous substances. Often the shell is the main element of the body, because it is this that holds the entire structure (for example, an adapter ring can be made from the shell, which connects pipes of different thicknesses). Another area of application for shells is construction. Often, industrial premises or cafes and restaurants have their own gas pipeline laid. It is installed in a concrete floor. In places where the pipe enters or exits the floor, it is protected from damage by a shell casing. You can buy shells at Region LLC. We manufacture shells using our own equipment, including according to customer drawings.

Shell manufacturing technology.

Shells can be made in different ways. The choice of method for manufacturing shells depends on the thickness of the metal and the strength requirements of the finished part. The most economical method of manufacturing shells is rolling, i.e. deformation of sheet material (steel, aluminum) along a certain direction. Rolling can be cold or hot, depending on the thickness of the material. As a rule, thin-walled shells are made by cold rolling, and thick-walled ones by hot rolling.

Rolling is carried out on a special machine - rollers. The sheet material from which the part must be made is laid between the shafts, which bend it to the required radius.

Metal rolling price

When indicating prices for rolling in price lists, many manufacturers clarify that this information is not a public offer and requires clarification. And there is no guile here, because the final cost of the project will depend on several factors:

metal from which the blanks are produced;
section thickness,
complexity of the workpiece: passing a sheet through rolls is much easier than rolling a circle;
bending radius;
number of workpieces for processing.

By the way, the last factor can affect the formation of a discount: the larger the order volume, the greater the percentage the price can be reduced.

Features of defects, description of technology

When deforming inside metal parts, distortions reach extreme values. The thickness also changes.

The metal is subjected to two types of deformation - it starts with elastic, then moves to plastic. The smaller the bending radius, the more effort you need to make. This is due to the fact that the layer of metal in mm increases, which requires drawing.

Internal stresses may arise in the metal after metal rolling is completed. There are three types of such phenomena. They are also taken into account by those who work in the city of Obninsk.

Zonal stresses appear between individual sections of the section and parts of the part. It is this deformation that most contributes to the appearance of defects, which is why it is considered the most dangerous. Afterwards, warping and cracks appear on the surface of the rolls and other parts. Their properties depend on the temperature gradient that appears between different parts of the part during temperature exposure. mm is also used for measurement.
Changes in the structural type occur in grains either inside or outside. The appearance of stress is associated with different expansion coefficients with different characteristics. The formation of new phases of different volumes can also lead to additional items. This negatively affects the production of rolled and other types of parts. Obninsk is no exception.
Voltages of the third group appear inside the volume of several cells that make up the crystal lattices. This can make hemming the edges more difficult.

Our advantages

The Department 13 enterprise has large production capabilities for metal processing and manufacturing of metal products and structures. The company has been providing rolling services for many years. Extensive experience allows us to perform work of any complexity. Cooperation with us has the following advantages:

The presence of modern equipment and experienced employees will ensure the implementation of all types of rolling and a high level of quality of metal processing.
Short order execution times.
Reasonable price for services provided.
Possibility of producing both large batches and single products.
Discounts for large volumes.
Carrying out work of any complexity.
The company systematically carries out diagnostics of equipment and grinding of equipment. Strict quality control is carried out,
Thanks to the favorable location of production facilities, we provide rolling services both in Moscow and in the regions.

The company will promptly provide metal rolling services in accordance with the customer’s technical documentation. If it is not available, our employees can help with the development of the necessary drawings. They will also advise and answer all your questions. Products are manufactured in accordance with drawings, technical documentation, as well as GOST standards or other regulatory documents. The company is ready to make non-standard products. We begin the work only after agreeing on the cost and all technical issues.

If necessary, you can also order further processing of products from us through electric welding, grinding, etc. You can make shells, cones, containers and other structures. Metal rolling in Moscow at our enterprise will allow us to meet the strict requirements of the customer. Products can also be delivered by road or rail to any region of the Russian Federation.

Why are shells so necessary?

Column equipment and pipelines of non-standard shapes are made from shells. Each product is accompanied by a document.

Structural elements of solid propellant rocket motor

3.1. Solid propellant housings

The main power element of a solid propellant rocket engine is its body. The body is made by casting, stamping, turning, as well as using welding and winding. The materials for the body are low-carbon, easily welded steel; cold-rolled steels with a strictly directional arrangement of fibers; aluminum, magnesium, titanium alloys; fiberglass.

From the point of view of design and strength calculations, the engine housing shell is considered as a thin axisymmetric shell. Housing shells can be classified: according to the material used - metal and non-metal; in shape, Fig. 3.1., - into cylindrical, spherical and conical, and non-metallic shells can have the shape of a “half-cocoon” or “cocoon”; according to the presence of welds (metal shells) - into welded (with circular, spiral and longitudinal seams) and seamless (rolled and seamless). The shells can be smooth, have local elements glued, soldered or welded to them. The shells can end with flanges or transitions into the bottoms. Finally, the shells can be single or multi-sectional, and have intermediate stiffening belts (rings, bandages, clamps).

Rolling - how to do it, with what tools?

Special presses or machines are the devices that can handle these types of processing. Bending of shells cannot be done only by hand. The same goes for bending. Rolling technology must be observed as strictly as possible, otherwise the desired result cannot be achieved when working with the installation or rolling.

Three-roll rollers are a type of equipment that is often used to solve such problems. There are several types of devices:

Manual.
Mechanical - in St. Petersburg and other cities they are widespread.
With an electric drive - these are widely used in the city of Obninsk.

Most often in St. Petersburg and other cities, the option is used when the rollers are arranged in the form of a triangle. Two are at the bottom and one is at the top. The diameters of the rolls are different, everything is determined by the characteristics of the required part. Rolling length is in the range of 340-3000 mm.

Electrical equipment is a much easier option to use. This can be understood by reading the regulatory documentation. But its cost is not affordable for everyone. If you do not plan to open large-scale production, then you can get by with simpler installation options. These have a simple angle.

Video: making a shell from stainless steel 3 mm thick.

Equipment used

Rollers

Specifications	Magnitude
The largest thickness of the sheet to be bent during radius bending	50 mm
The smallest thickness of the sheet to be bent during radius bending	1 mm
Minimum bending radius	35 mm

Manufacturing

A typical technological process for the production of shells includes the following stages:

Cleaning the workpiece (removing scale and traces of corrosion).
Performing straightening of sheet metal.
Marking blanks, cutting them.
Cutting sheets into blanks.
Preparation of edges for welding work.
Assembly of blanks.
Performing card welding.
Rolling (circular bending) of shells.
Welding joints.
Edit.
Control.

Edge preparation

The operation is necessary to obtain the required edge shape and get rid of defects that arose when cutting the sheet. The shape of the edges must meet industry standards, specifications and requirements. Methods for processing the edges of shells for welding should not lead to mechanical damage. Possible options:

Preparation of edges using an abrasive wheel with cleaning on both sides of the sheet plane in the areas of cutting edges and points of future welding, at a distance of 40 mm from the ends.
Cleaning the edges using an electric grinder, on a tile stand, until cracks, rust, and scale are completely removed.
Processing of edges using the milling method is carried out by securing the workpieces on the tables of milling machines of one type or another. Milling tools are milling heads and cutters. The edges for transverse seams in the bottoms and shells are processed on lathes and boring machines.
Local edge cleaning and small amounts of work are performed using a pneumatic chisel.

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Metal bending and rolling

Flexible and rolling are often equated.
This is not entirely true, although the second technology is, in fact, a more complex version of the first. And the simplest bending and rolling are performed on fundamentally different equipment. Let’s take, for example, the most popular rolled product in processing—sheet metal. To bend it in the usual way, you will need a sheet bending machine, and this operation will be directly performed by its two leading elements - the matrix and the punch. In the case of rolling, the sheet is bent on rollers (rollers) - special rollers. Sometimes, in order to acquire the desired shape, the workpiece passes through a whole system of these mechanisms.