What science steel is used for the leaf spring. Spring-spring steels. Application of spring steel

31. Spring steel

Steels intended for the manufacture of springs and springs must allow large elastic deformations and have plastic properties that ensure the operation of twisted and other springs without breakage during overloads, must withstand cyclic loads (especially of an oscillatory nature). In accordance with this, steels for springs and springs must have a high elastic limit and endurance limit, sufficient toughness and ductility. The yield strength of carbon spring steels after final heat treatment should exceed 800 N/mm2, and of alloyed steels -1000 N/mm2. Plasticity indicators should be δ≥5% and ψ≥20%. Carbon steels for springs and leaf springs have low corrosion resistance and low relaxation resistance. The low hardenability of these steels limits their use - usually only for the manufacture of springs and springs of small cross section. Alloy steels have higher strength properties, increased toughness and resistance to brittle fracture, higher relaxation resistance, quenchability in oil and even in air. These steels are more preferred for the manufacture of springs and leaf springs. Mechanical properties (minimum) of spring steels are provided by GOST 14959-79. These steels are: 65, 70.75, 85, 65G,65G2, 70G, 60S2,48,70SZA, 50KhG, 55KGR, 60GSA, 50KhGFA, etc. Heat treatment modes: quenching temperature in oil 820 ... 870 ° C, tempering temperature 420 …480°С.

Wear-resistant steels are used (used) for the manufacture of machine parts operating under friction conditions:

ball bearing,

graphitized,

High manganese.

Ball bearing steels (ШХ15, ШХ20) are used for the manufacture of bearing balls and rollers.

According to the chemical composition (GOST 801-78) and structure, these steels belong to the class of tool steels.

Graphitized steel (high carbon, containing 1.5 - 2% C and up to 2% Cr) is used for the manufacture of piston rings, pistons, crankshafts and other shaped castings operating under friction conditions.

Graphitized steel contains a ferrite-cementite mixture and graphite in the structure.

Graphitised steel U16 (EI 336)

The amount of graphite can vary significantly depending on the heat treatment mode and carbon content.

Graphitized steel after hardening combines the properties of hardened steel and gray cast iron.

Graphite in such steel plays the role of a lubricant.

High-manganese steel G13L, containing 1.2% C and 13% Mn, is used for the manufacture of railway crosses, track links, etc.

This steel has maximum wear resistance when it has a single-phase austenite structure, which is ensured by quenching (1000-1100°C) while cooling in air.

Hardened steel has a low hardness (HB 200), after hard hardening, its hardness rises to HB 600.

Ball bearing steels

Steels for the manufacture of bearing parts (rings, balls, rollers) are considered structural, but in terms of composition and properties they are instrumental. High-carbon chromium steel ШХ15 has the greatest application. The hypereutectoid content of carbon (0.95%) and chromium (1.3...1.65%) in it ensures that, after hardening, high uniform hardness, resistance to abrasion and sufficient toughness are obtained. Steel quality and bearing life are adversely affected by carbide segregations, banding and mesh. The physical uniformity of steel 50 is adversely affected by non-metallic (sulfide and oxide) and gas inclusions, macro- and microporosity. Steel ШХ15 is used for parts of small sections. For parts of larger bearings, in order to improve their hardenability, chromium-silicon-manganese steels ShKh15SG and ShKh20SG are used.

For the manufacture of large-sized bearing parts for rolling mills, railway transport, operating in difficult conditions with high shock loads, case-hardening steel 20X2H4A is used.

33. Corrosion-resistant (stainless ) become. Carbon and low-alloy steels are susceptible to corrosion, i.e., they are destroyed by the chemical effects of the environment. According to the mechanism of the process, two types of corrosion are distinguished: chemical and electrochemical. The phenomena that occur during electrochemical corrosion are similar to the processes in a galvanic cell. Steels that are resistant to electrochemical corrosion are called corrosion-resistant (stainless). Steel has anti-corrosion properties if it is alloyed with a large amount of chromium or chromium and nickel.

Chromium corrosion-resistant steels. The content of chromium in steel must be at least 12%. With a lower chromium content, steel is not able to resist corrosion, since its electrode potential becomes negative. Steel grades 12X13, 40X13, 12X17.08X17T are widely used.

Chromium-nickel corrosion-resistant steels. These steels contain a large amount of chromium and nickel, little carbon and belong to the austenitic class. In addition to austenite, these steels contain chromium carbides. To obtain a single-phase austenite structure, steel, for example, grade 12X18H9, is quenched in water from a temperature of 1100 ... 1150 ° C. This achieves the highest corrosion resistance, but the strength is relatively low. To increase the strength, steel is subjected to plastic deformation in a cold state.

Austenitic chromium-nickel steels have greater corrosion resistance than chromium steels, and they are widely used in the chemical, oil and food industries, automotive, transport engineering, and construction.

Heat-resistant steels and alloys. These include steels and alloys that can work under load at high temperatures for a certain time and at the same time have sufficient heat resistance. The decrease in the strength of steel is affected not only by the increase in temperature itself, but also by the duration of the applied load. In the latter case, under the action of a constant load, the steel "creeps", therefore this phenomenon is called creep. For carbon and alloy structural steels, creep is observed at temperatures above 350°C. The factors contributing to the increase in heat resistance are:

high melting point of the base metal; the presence of a solid solution and fine particles of the hardening phase in the alloy; plastic deformation causing hardening; high recrystallization temperature; rational doping; thermal and thermomechanical processing; introduction to heat-resistant steels in fractions of a percentage of elements such as B, Ce, Nb, Zn.

Heat-resistant steels and alloys are classified according to the main feature - the operating temperature. For operation at temperatures up to 350 ... 400 ° C, ordinary structural steels (carbon and low alloyed) are used. For operation at a temperature of 400 ... 550 ° C, alloyed steels of the pearlite class are used, for example, 15XM, 12X11MF. For these steels, the main characteristic is the creep limit, since they are intended mainly for the manufacture of parts of boilers and turbines, for example, steam pipes and superheaters, which are relatively lightly loaded, but operate for a very long time (up to 100,000 hours). These steels contain little chromium and therefore have low heat resistance (up to 550...600°C). For operation at a temperature of 500 ... 600 ° C, martensitic steels are used: high-chromium, for example 15X11MF for steam turbine blades; chrome-silicon (called silchromes), for example 40X9C2 for motor valves; complexly alloyed, for example 20X12VNMF for disks, rotors, shafts, turbines. For operation at a temperature of 600 ... 750 ° C, austenitic steels are used, divided into non-hardened (non-aging), for example, steel 09X14H16V, intended for pipes of superheaters and pipelines of ultra-high pressure installations, and hardened (aging) complex alloy steels, for example, steel 45X4H14V2M, used for valves motors, pipeline parts, and steel 40Kh15N7G7F2MS for gas turbine blades. The heat resistance of steels of the austenitic class is 800 ... 850 ° C. For operation at 800 ... 1100 ° C, nickel-based heat-resistant alloys are used, for example KhN77TYuR, KhN55VMTFKU for turbine blades. These alloys are aging and are subjected to the same heat treatment (quenching and aging) as aging steels of the austenitic class. Heat resistance of nickel-based alloys up to 1200°C.

Depending on the basic structure obtained by cooling steel in air after high-temperature heating, corrosion-resistant and heat-resistant steels are divided into six classes. The martensitic class includes steels with the main structure of martensite. They contain up to 17% Cr and small additions of tungsten, molybdenum, vanadium and nickel. These are steels 15X5, 20X13, 15XM, 20XM, etc. The martensitic-ferritic class includes steels containing in the structure, in addition to martensite, at least 10% of ferrite. These steels contain 11...17% Cr and a small amount of other elements. The carbon content does not exceed 0.15%. Their heat treatment consists of quenching with tempering or normalization with tempering. These are steels 12X13.14X17H2, 15X12VNMF, 18X12VMBFR. The ferritic class includes steels having a ferrite structure. They contain a small amount of carbon, up to 30% Cr and small additions of titanium, niobium and other elements. Steel: 08X13, 12X17T, 15X25T, 15X28. The austenitic-ferritic class includes steels having the structure of austenite and martensite, the amount of which can be varied over a wide range. Steels: 20Kh13N4G9, 09Kh15N8Yu, 07Kh16N6, 09KH17N7YUZH, 08KH17N5M3. The austenitic-ferritic class also includes steels having the structure of austenite and ferrite (more than 10% ferrite). A special group of steels of the austenitic class is economically alloyed with nickel and nickel-free steels.

If you have some free time and an unnecessary spring from a truck or other car, then you can make a rather beautiful and unique knife with your own hands. Perhaps the first time it will not be completely perfect, but the main thing is that it is made by hand. The main charm of this homemade product is that the knife can be of almost any shape, you just need to turn on a little imagination.

Materials and tools for homemade:
Bulgarian;
truck spring;
file;
epoxy resin;
linseed oil.

Step 1. Material preparation
Using a grinder, the author cut it into three parts, since the part has a different thickness and rounded shape, it is necessary to choose the optimal part for this type of knife. That part of the spring, which is ideally suited for the blade, is sawn in half, as a result, there are two identical blanks.

Since the spring has a thickness of about 8 mm, and there are practically no such knives, it is necessary to remove the thickness with emery for a long time to the desired one. Then on the machine you need to shape the blade, it is desirable that there be a fine-grained stone, otherwise the knife will look rough and a little not neat.

Structural carbon or high carbon steels include spring steel. To give it narrowly targeted properties, it is alloyed in small quantities with 2-3 elements, up to 2.5% in total. But the use of these steel grades is not limited to the manufacture of springs. This group is called so, due to the fact that this name most strongly reflects their main feature - elasticity.

Characteristics of spring steels

Spring steels are characterized by increased yield strength (δ B) and elasticity. This is the most important characteristic of the metal - to withstand mechanical loads without changing its original shape. Those. a metal subjected to tension or vice versa compression (elastic deformation), after removal of the acting forces from it, must remain in its original form (without permanent deformation).

Grades and scope of spring steel

According to the presence of additional properties, spring steel is divided into alloyed (stainless) and carbon steel. The alloyed steel is based on carbon steel with a C content of 65-85% and is alloyed with 4 main elements, all or selectively, each of which introduces its own characteristics:

1. chromium;
2. manganese;
3. silicon;
4. tungsten.

Chromium - at a concentration of more than 13%, it works to ensure the corrosion resistance of the metal. With a chromium concentration of about 30%, the product can operate in aggressive environments: acidic (except sulfuric acid), alkaline, aqueous. Corrosive spring steel is always alloyed with a second accompanying element, tungsten and/or manganese. Working t up to 250 °C.

Tungsten is a refractory substance. When its powder enters the melt, it forms numerous centers of crystallization, grinding the grain, which leads to an increase in plasticity without loss of strength. This brings its advantages: the quality of such a structure remains very high during heating and intense abrasion of the surface. During heat treatment, this element retains a fine-grained structure, eliminates the softening of steel during heating (during operation) and dislocation. During hardening, it increases the hardenability, as a result of which the structure becomes homogeneous to a greater depth, which in turn increases the service life of the product.

Manganese and silicon - usually participate in doping mutually, and the ratio always increases in favor of manganese, up to about 1.5 times. That is, if the silicon content is 1%, then manganese is added in an amount of 1.1-1.5%.

Refractory silicon is not a carbide-forming element. When it enters the melt, it is one of the first to take part in crystallization, while pushing carbon carbides to the grain boundaries, which accordingly leads to hardening of the metal.

Manganese can be called a structure stabilizer. By simultaneously distorting the metal lattice and strengthening it, manganese eliminates the excessive strength of silicon.

In some steel grades (when the product is operated in high-temperature conditions, at t above 300 ºC), nickel is added to the steel. It eliminates the formation of chromium carbides along the grain boundaries, which lead to the destruction of the matrix.

Vanadium can also be an alloying element, its function is similar to that of tungsten.

In spring grades, such an element as copper is specified, its content should not exceed 0.15%. Because being a fusible substance, copper concentrates at the grain boundaries, reducing strength.

The spring brands include: 50HG, 3K-7, 65G, 65GA, 50HGFA, 50HFA, 51HFA, 50HSA, 55S2, 55S2A, 55S2GF, 55HGR, 60G, 60S2, 60S2A, 605, 70, 70G,75, 80, 82XA, , 60S2HFA, 65S2VA, 68A, 68GA, 70G2, 70S2XA, 70S3A, 70HGFA, SH, SL, SM, DM, DN, CT-2.

Grades of such steel are used for the manufacture of not only springs and springs, although this is their main purpose, which characterizes the main property. They are used wherever there is a need to give the product elasticity, plasticity and strength at the same time. All parts that are made from these grades are subject to: stretching and compression. Many of them experience loads that periodically replace each other, and with a huge cyclic frequency. This:

• bearing housings that experience compression and tension at each point with high frequency;
• friction discs experiencing dynamic loads and compression;
• thrust washers, most of the time they experience compressive loads, but a sharp change in tension can also be added to them;
• brake bands, for which one of the main tasks is elasticity under repeated stretching. With this aging and wear dynamics, stronger steel (with less elasticity) is subject to rapid aging and sudden failure.

The same applies to gears, flanges, washers, collets, etc.

Marking

Spring-spring steels can be grouped by position:

• unalloyed with a carbon content of 65-85% - inexpensive general purpose steel;
• manganese-silicon - the cheapest with high physical and chemical indicators;
• chromium-manganese - stainless steel, works in aggressive environments at t -250 +250 C;
• additionally alloyed with and / or tungsten, vanadium, boron - they are steels with an increased service life due to a homogeneous structure, an excellent ratio of strength and ductility due to crushed grain and withstand high mechanical loads. Used at facilities such as railway transport.

Marking of spring steels is carried out as follows. Let's take a look at the example of 60C2HFA:

• 60 - percentage of carbon in tenths (carbon is not indicated in the letter value);
• C2 - the letter designation of silicon with index 2, indicates an increased standard content (1-1.5%) by 2 times;
• X - the presence of chromium up to 0.9-1%;
• Ф - tungsten content up to 1%;
• A - the added letter index A at the end of the marking indicates the minimum content of harmful impurities of phosphorus and sulfur, not more than 0.015%.

Production

Depending on further processing and the final look of the part, steel is supplied in sheets, wire, hexagons, squares. High performance of the product is provided by 2 components:

1. the structure of the metal, which is determined by the chemical composition and subsequent processing;
2. the presence of non-metallic inclusions in the structure, more precisely, the minimum number and size, which is eliminated at the stage of smelting and pouring;
3. the shape of the part (spiral, arc) and its dimensions, which is determined by the calculation method.

When the spring is stretched, the inner and outer sides of the coils experience different degrees of stress: the outer ones are less subject to stretching, while the inner ones experience the greatest degree of deformation. The same applies to the ends of the spring: they serve as an attachment point, which increases the load in these and adjacent places. Therefore, steel grades have been developed that are preferably used in compression or tension.

Thermomechanical processing

Without exception, all spring steels are subjected to thermomechanical processing. After it, the strength and wear resistance can increase by 2 times. The shape of the product is given in the annealed state, when the steel has the maximum possible softness, after which it is heated to 830-870 C and cooled in an oil or water medium (only for grade 60 CA). The resulting martensite is tempered at a temperature of 480 ºC.

Spring steel is used for the manufacture of springs, springs, buffers and other parts used in the hardened and tempered state, operating under conditions of dynamic and alternating loads. The specified steel should have high limits of elasticity (yield) and endurance with sufficient ductility and toughness. These properties are achieved after heat treatment (hardening and subsequent medium tempering). As a spring-spring, carbon steel with a high carbon content is used, and for a responsible purpose - alloy steel.

GOST 14959-79 applies to hot-rolled and forged long products with a diameter or thickness of up to 250 mm, as well as to calibrated products and with special surface finishes.

The standard classifies rolled products from spring-loaded carbon and alloy steel according to the processing method, chemical composition and other characteristics.

According to the processing method, rolled products are divided into: hot-rolled and forged with a special surface finish, hot-rolled round with a turned or ground surface.

According to the normalized characteristics and application, rolled products are divided into categories 1, 1A, 1B, 2, 2A, 2B, 3, ZA, ZB, ZV, ZG, 4, 4A, 4B. Rolled products of categories 2, 2A, 2B, 3, ZA, ZB, ZV, ZG are intended for the manufacture of elastic elements - springs, springs, torsion bars, etc.; categories ZA, ZB, ZV, ZG - for the manufacture of automobile springs and springs; categories 1, 1A, 1B, 4, 4A, 4B - for use as a structural material. Rolled products are manufactured in a heat-treated state (annealed or highly tempered) - categories 1A, 2A, 2B, 3V, 4A or without heat treatment - categories 1, 1B, 2, 2B, 3, ZB, ZG, 4, 4B.

According to the chemical composition, steel is divided into high-quality and high-quality (the letter A is placed at the end of the designation of the grade of high-quality steel). The mass fraction of sulfur and phosphorus in high-quality steel is no more than 0.035% (each element separately), and in high-quality steel - no more than 0.025%.

In steel of all grades, the residual mass fraction of copper should not exceed 0.20%, and nickel - 0.25%.

Properties, technical requirements, heat treatment, purpose.

Carbon spring steel is cheaper than alloy steel, but has low corrosion resistance and low hardenability. It is used only for the manufacture of springs of small cross section. Alloying of steel (silicon, manganese, chromium, and for particularly critical parts also nickel, vanadium, tungsten) increases the strength properties, hardenability, endurance limit and relaxation resistance.

In the process of relaxation, part of the elastic deformation passes into plastic (residual), therefore, springs and springs may lose their elastic properties over time. Alloy steels, having increased relaxation resistance, provide more reliable operation of machines, instruments, automatic machines than carbon steels.

The fatigue limit of spring steel is affected by the state of the rolled product surface, since external defects can serve as stress concentrators and cause fatigue cracks. Therefore, higher requirements are imposed on the quality of the rolled surface. So, for example, on the surface of bars, strips and coils intended for hot working and cold drawing, there should be no rolled bubbles, rolling films, sunsets, rolled and forged dirt and cracks. Surface decarburization also reduces the fatigue strength of steel, so the depth of the decarburized layer of steels is regulated.

High demands are also placed on the macrostructure of steel: on fractures or on pickled transverse templates, there should be no remnants of a shrinkage cavity, looseness, bubbles, delaminations, cracks and other defects.

It should be noted that the elastic and strength properties of steel increase when isothermal hardening is used instead of conventional. The endurance limit, and hence the service life of the springs and springs, can be increased by shot blasting and hydroabrasive treatment (surface work hardening).

A knife is a great thing that can be useful not only as an excellent tool, but also as a wonderful souvenir. Every boy will be happy with such a gift. If the knife is made by hand, then it immediately becomes a unique value in the eyes of the owner.

Adults also do not always use knives exclusively for domestic purposes - many people collect them. Everyone has different selection criteria, but everyone knows that high-quality steel is a prerequisite for a good knife. But a beautifully crafted handle can make just as much of an impression as a durable blade that can hold a sharp edge for a long time.

What is the peculiarity of a knife from a spring?

The reason for the popularity of such a product as a spring knife lies in the properties of the metal. High wear resistance and strength, combined with high plasticity, have allowed many generations of craftsmen to use springs as the main source of raw materials.

Springs are made of spring steel 65G, but other grades can be used: 50HGSA, 50HGA, 50HFA. These are also spring steels - it is possible to determine which of them is taken as the material for the blade only with the help of chemical analysis. Or according to the nuances of the behavior of the metal during processing, but only experienced craftsmen can handle this. For a novice manufacturer, the difference between the listed materials will be almost imperceptible.

Application of spring steel

65G is considered one of the cheapest spring steels. At the same time, it has a number of unique properties that make it indispensable for creating springs. Spring steel for a knife contains chromium, nickel, manganese, silicon. These elements give the properties for which this particular material is chosen by manufacturers:

• good flexibility;
• high impact strength;
• hardness;
• wear resistance;

Heat treatment plays a big role in improving the quality of the material. Steel becomes stronger, its hardness increases. Unfortunately, it is not sufficiently resistant to corrosion - it tends to rust. But the advantages outweigh the disadvantages and it is often used as a blade material.

These knives are used in a variety of fields. First of all, as kitchen appliances – strong, strong, durable – what else do you need for daily work in the kitchen and, for example, for cutting meat? The same considerations forced hunters, fishermen and tourists to try to get this high-quality "home-made" into their arsenal. Therefore, many craftsmen made tourist and hunting knives for sale.

Due to the good characteristics of steel, these knives were popular among the military. Conscripts, who had access to metalworking tools, made army knives in artisanal conditions. Over time, manufacturers began to aim at more serious products: axes, swords, machetes, katanas. Due to their good toughness, spring steels are excellent for forging. Forging can make a blade of any shape, even the most bizarre.

How to make a knife from a spring

Making a knife from a spring can take a lot of time and effort, especially if a person is doing it for the first time. But spring steel lends itself well to processing and “endures” the mistakes of a beginner, so it is best to create your first knife from it.

Usually, the material is found in the open air: on the street, in car depots, next to garages, in car dumps and other similar places. Therefore, the spring can be covered with dirt and rust and must be thoroughly cleaned before work. If it is necessary to straighten a curved spring, then it is heated to red, and then allowed to cool under normal conditions - at room temperature.

How to make a knife from a spring using forging

All spring steels, including 65G, have one quality in common: they lend themselves perfectly to forging. Forged spring steel knives will be more reliable and durable, because during processing the metal is hardened due to plastic deformation and changes in the macrostructure.

Before forging the spring, it is necessary to cut out the profile of the future blade from it. Then the workpiece is securely fastened, and heated to red. Forging creates a point and blade. In this way, it is easy to give the blade the desired shape, as well as set its width. Forging from the spring is good at making axes and various exotic items, such as a machete or a sword.

The blade is allowed to cool to ambient temperature after the work is completed.

How to carve a knife from a spring with your own hands

It is necessary, first of all, to decide on the appearance of the future product. The shape depends on the purpose of the knife: kitchen, hunting, souvenir or some other. As a result, the blade can be any - only the imagination and the capabilities of the manufacturer affect this. If the choice is made, then you need to take a ready-made template or make it yourself from cardboard or thick paper.

Further, in order to make a knife from a spring with your own hands, you must be ready to start working with metal. First, the template must be attached to a metal workpiece and circled with a marker, pencil, scriber (GOST 24473-80) or other marking tool. According to the contour obtained by means of a template, it is required to cut out the profile of the product. The following tools will work:

• band-saw;
• angle grinder, she is also a "grinder" - it is important not to overheat the workpiece when cutting;
• drilling machine or drill - in this case, holes are drilled along the contour, then the partitions between them are broken or cut out;
• you can use a hand tool;

The processing process itself is quite simple, although it requires a certain concentration in order to cut the workpiece in accordance with the markup. When the processing is successfully completed and the workpiece began to match the template, then you can begin to form the blade. The main task is to make bevels. The blade is again marked by determining the dimensions of the bevels. Further processing should strictly adhere to the markup.

It is best to use an electric sharpener for the job. A belt grinder and a grinder are also suitable, but, in the case of the latter, good command of the tool is required. You can grind the bevels manually - with a file. On this, the metal work should be completed, because then the blade will undergo heat treatment, after which it will be very difficult to do anything else with the workpiece.

Blade hardening

The main type of heat treatment is hardening. It is needed so that the blade is strong and can remain sharp for a long time after sharpening. There are different approaches:

- hardening, with heating of the cutting edge only;

- hardening of the cutting edge by heating the entire product;

— hardening with vacation;

- full hardening;

In the first case, only the extreme part of the blade is heated to a non-magnetic state, after which it is placed in oil and kept until the oil stops bubbling. The second method is more complicated: the whole knife heats up, but only a third is required to immerse it in oil - so that the cutting edge is covered with liquid.

Hardening and tempering is a method in which the cooling of the workpiece is carried out in two stages: first at an elevated temperature, but below the quenching temperature, then at room temperature.

The easiest hardening method is to fully harden the blade, but with this method there is a chance that the blade will lead. Then it is necessary to straighten the damaged workpiece. This can be done either by preheating the blade or cold.

Handle manufacturing

The handle can be made from almost any raw material, but wood, plastic, leather, and bone are especially popular. Type-setting pens with alternating layers, for example, leather and birch bark, look beautiful.

Bone is a traditional material for making a variety of trinkets and household items. With the skill of bone carving, you can make a unique, beautiful pen. But the easiest way is to take two wooden or plastic pads, place them on both sides of the shank and fasten them together with rivets, and for greater strength, also with epoxy glue. Sometimes screws and nuts are used for fastening, but if appearance is important, then it is better not to use them.

The handle should be comfortable, so you need to pay great attention to its processing. For this, files are used first, and then sandpaper. If the overlays are wooden, then they must be impregnated with oil to ensure the durability of the wood. Impregnation emphasizes the structure of the tree and gives the product an attractive appearance. After fixing the handle, its final grinding is carried out.

Work on the knife from the spring is almost complete, it remains only to sharpen it. For this use:

• bars;
• musats;
• grinding machines;
• mechanical sharpeners;
• electric sharpeners;

Really good results are obtained using a whetstone or an electric sharpener. To sharpen a knife well with a bar or grindstone, it will take a lot of time. If it is enough to spend about half an hour on an ordinary kitchen knife, then leveling and sharpening a long forged knife can take several days.

For better control of the sharpening process, the whetstone is placed on a stable horizontal surface. Its optimal size is about one and a half times longer than the blade. It is required to start sharpening with a coarse whetstone, with a large grain. You need to continue until a burr appears. After that, a fine-grained stone is taken, then the process continues with its help. In order for a home-made knife from a spring to become sharp, and the sharpening lasts for a long time, the following rules must be observed:

• movement is carried out by translational movements of the knife along the bar - the cutting part forward;
• the end of the bar and the end of the blade should "meet". It is necessary to synchronize the displacement of the knife across the bar (from the handle to the blade) and the movement of the knife along the bar;
• the plane of the blade and the surface of the bar should be at an angle of 20 to 25 degrees - this is the universal sharpening angle. Depending on the purpose of the knife, the angle may vary, but it is important that it be kept constant all the time while the knife is sharpening;

At the end, it is necessary to polish the blade in order to keep the knife sharp for a long time. To do this, take a grindstone with the smallest grain. Then, carefully, so as not to spoil what has already been done, the burr is removed.

Sharpening is a process that requires patience and care. Skill comes only with experience, so anyone who does not want to wait can use an electric sharpener. This saves time and also keeps the knives in excellent condition.

Making a knife is a complex process that requires attention, concentration, thoroughness, and metalworking skills. But the work will not be in vain, because in the end you will get a wonderful product created by yourself. The more love and diligence the master approached the matter, the better the product will be. Even a beginner, if he is patient and persevering, will be able to master the skills and also become proud of the results of his work.