Quenching and tempering of steel 65G: hardness, technology, video

Chemical composition

The 65G spring steel grade is a combination of the following ingredients:

carbon (C) – 0.65-0.7%;
silicon (Si) – 0.17-0.37%;
manganese (Mn) – 0.9-1.2%;
nickel (Ni) and chromium (Cr) – with a limit of 0.25%;
sulfur (S) and phosphorus (P) – no more than 0.035%;
copper (Cu) – up to 0.2%;
iron (Fe) – 97%.

Chemical composition of grade 65G

The main task of the products made is to maintain maximum durability and elasticity. This effect can be achieved by adding 1% manganese. The remaining components are classified as impurities and are added in accordance with government standards.

Common parameters

The substances included in this material and its further heat treatment provide:

high wear resistance;
good impact strength;
tensile strength;
high resistance to impact.

The absence of a large number of alloying elements allows for a relatively low price of this steel.

To obtain the specified parameters, 65G steel is hardened at a temperature of 800 to 830 ºC. Tempering is carried out at a temperature of 160 to 200 ºC; this tempering is called high. Cooling is performed in air. Such heat treatment modes make it possible to obtain a product with a surface hardness of 45-47 HRC.

The technologist, when designing the heat treatment process, must remember that 65G steel and its analogues are not afraid of overheating, but when hardening is performed at the upper points of the temperature range, the impact strength may decrease.

Temperature selection

For the correct completion of the hardening process, the correct selection of temperature, which depends on the material used, is very important.

Steels based on carbon content are divided into hypoeutectoid - less than 0.8% and hypereutectoid - more than 0.8%. Steel with carbon less than 0.4% is not hardened due to the resulting low hardness. Hypoeutectoid steels are heated slightly above the temperature of the phase transformation of pearlite and ferrite to austenite. This occurs in the range of 800-850°C. Then the workpiece is quickly cooled. When cooled sharply, austenite transforms into martensite, which has high hardness and strength. A short holding time makes it possible to obtain fine-grained austenite and fine-needle martensite; the grains do not have time to grow and remain small. This steel structure has high hardness and at the same time low brittleness.

Microstructure of steel

Hypereutectoid steels are heated slightly lower than hypoeutectoid steels, to a temperature of 750-800°C, that is, incomplete hardening is performed. This is due to the fact that when heated to this temperature, in addition to the formation of austenite, a small amount of cementite, which has a higher hardness than martensite, remains undissolved in the metal melt. After rapid cooling, austenite transforms into martensite, and cementite remains in the form of small inclusions. Also in this zone, carbon that has not had time to completely dissolve forms solid carbides.

In the transition zone during high-frequency quenching, the temperature is close to the transition temperature, and austenite with ferrite residues is formed. But, since the transition zone does not cool down as quickly as the surface, but cools down slowly, as during normalization. At the same time, the structure in this zone improves, it becomes fine-grained and uniform.

After cooling, high compressive stresses remain on the metal surface, which increase the performance properties of the part. Internal stresses between the surface layer and the middle must be eliminated. This is done using low-temperature tempering - holding at a temperature of about 200°C in an oven. To avoid the appearance of microcracks on the surface, it is necessary to minimize the time between hardening and tempering.

You can also carry out the so-called self-tempering - cool the part not completely, but to a temperature of 200 ° C, while heat will remain in its core. Then the part should cool slowly. This will equalize internal stresses.

https://youtube.com/watch?v=vUaDCaVcjac

Heating the metal

All steel hardening methods consist of:

heating steel;
subsequent holding to achieve through-heating of the product and completion of structural transformations;
cooling at a certain speed.

Carbon steel products are heated in chamber furnaces. In this case, preheating is not required, since these steel grades are not subject to cracking or warping.

https://youtube.com/watch?v=I-br0B8ocpI

Complex products (for example, a tool with protruding thin edges or sharp transitions) are preheated:

in salt baths by immersing two or three times for 2 - 4 seconds;
in separate ovens up to a temperature of 400 - 500 degrees Celsius.

Heating of all parts of the product should proceed evenly. If this cannot be achieved in one step (large forgings), then two holding times are made for through heating.

If only one part is placed in the oven, the heating time is reduced. For example, one 24 mm thick disk cutter heats up within 13 minutes, and ten such products heat up within 18 minutes.

Methods for preventing scale formation and critically reducing carbon concentrations

The purpose of steel hardening is carried out taking into account what qualities the part should have. The process of rebuilding the atomic grid is associated with high risks of the appearance of various defects, which is taken into account at the stage of development of the technological process.

Even the most common methods, for example, quenching steel in water, are characterized by the appearance of scale or a significant increase in the fragility of the structure with a decrease in carbon concentration. In some cases, steel hardening is carried out after finishing, which does not allow even minor defects to be eliminated. This is why technologies have been developed that reduce the likelihood of scale or cracks. An example is a technology where steel is hardened in a protective gas environment. However, complex methods of steel hardening significantly increase the cost of the procedure, since the gas environment is achieved when installing furnaces with a high degree of tightness.

A simpler technology, in which carbon steel is hardened, involves the use of cast iron shavings or used carburizer. In this case, the steel for hardening is placed in a container filled with the materials in question, after which only heating is carried out. The hardening temperature is slightly adjusted taking into account the created shell of chips. The technology involves coating the outside of the container with clay in order to prevent the ingress of oxygen, which begins the oxidation process.

Heating temperature of steel during heat treatment

As previously noted, heat treatment also involves cooling steels, for which not only a water bath, but, for example, a salt bath can be used. When using acids as a coolant, one of the requirements is periodic deoxidation of steels. This process eliminates the possibility of a decrease in the carbon concentration in the surface layer. To carry out the deoxidation process, boric acid or charcoal is used. Also, do not forget that the process of deoxidation of steels leads to the appearance of flames on the workpiece while it is lowered into the bath. Therefore, when hardening or hardening steels using salt baths, the developed safety precautions should be observed.

Considering these methods of heat treatment with subsequent cooling, it should be noted that they significantly increase the cost of the workpiece. However, today cooling in water or quenching while filling the chamber with oxygen does not allow increasing the properties of steel without the appearance of defects.

Steel hardening - technological process

Characteristics and properties

Having in its chemical composition 0.75...0.85% carbon, as well as a small amount of other elements - silicon, manganese, chromium, nickel and copper - U8 steel is ectectoid. With reduced manganese and silicon contents, the critical cooling rate always increases. Therefore, in practice, U8 steel is used only for the manufacture of metalworking tools with small overall dimensions. Hardening of steel of this type allows the use of very harsh cooling media (water or aqueous solutions of salts). Thus, this steel is not hardenable: the core remains viscous, and the hardness obtained as a result of preliminary annealing of the workpieces remains almost the same.

Scheme of structural transformations of U8

Quenching in water also has other negative consequences - with an increase in the cooling rate, the structure of the steel remains coarse-grained. During further processing (for example, forging), this feature can cause cracking of the forging, especially at significant degrees of deformation. Often, when quenched in water, the product loses its dimensions and warps, which forces additional calibration of the tool.

The temperature of the critical points of U8 steel is:

The beginning of the austenitic transformation from the initial pearlite when heated is 720 °C.
The end of the austenitic transformation is 740 °C.
The temperatures at which the transformation of austenite into pearlite begins and ends upon cooling coincide and are within 700 °C.
The martensitic transformation, starting at 810 °C, ends at 245 °C.

Hardness of steel after heat treatment

Steel 20Х13 - chromium stainless steel - Foundries of Russia

Classification of chromium stainless steelsSteel 08Х13Steel 12Х13Steel 30Х13

Steel 40Х13

Application of steel 20Х13

Steel 20Х13 is used in the manufacture of products for work in mildly aggressive environments:

atmospheric conditions other than sea;
aqueous solutions of salts of organic acids at room temperature;
solutions of nitric acid of weak and medium concentrations at moderate temperatures, etc.

Steel 20X13 is used in cases where products must have sufficiently high strength, as well as high ductility and toughness. 20X13 steel can be welded satisfactorily.

Steel 20X13 is also used as a heat-resistant material at temperatures up to 450-550 °C and as a heat-resistant material - up to 700 °C.

Chemical composition of steel 20Х13

Steel 20Х13 is included in steel type Х13 along with steels 08Х13, 12Х13, 30Х13 and 40Х13. It occupies its own range in carbon content - from 0.16 to 0.25%, the amounts of other alloying elements and impurities are the same as in other steels of the X13 type (Table 1).

Table 1 - Chemical composition of steel 20Х13 according to GOST 5632-72

Steel class 20Х13 according to GOST 5632-72

According to the GOST 5632-72 classification, steel 20Х13 belongs to the martensitic class.

Transformations and microstructure of steel 20Х13

When annealed steel 20Х13 is heated, the polymorphic alpha-gamma transformation occurs in it in the temperature range from 820 °C (Ac1) to 950 °C (Ac3). The temperature of point Ar1 is 780 °C.
During isothermal holding or slow cooling in the range of 800-550 °C, austenite decomposes into a ferrite-carbide mixture.
This ferrite-carbide mixture consists of high chromium ferrite and Cr23C6 type carbide.
When 20Х13 steel is rapidly cooled, a martensitic transformation occurs in it. The temperature at which the martensitic transformation begins is 220 °C.
With an increase in tempering temperature, there is a significant decrease in strength with an increase in ductility, as well as a decrease in corrosion resistance.

Steel range 20Х13

The following products are produced from steel 08Х13:

thick sheet according to GOST 7350-77;
thin sheet according to GOST 5582-75;
tape and roll according to GOST 4986-78;
long products according to GOST 5949-75;
hot-deformed pipes according to GOST 9940-81;
cold-deformed and heat-deformed pipes according to GOST 9941-81;
wire according to GOST 18143-72.

Mechanical properties of steel 20Х13

The mechanical properties of steel 20Х13 in various types of products are presented in Table 2.

Table 2 - Mechanical properties of steel 20Х13 at 20 °С

The effect of decreasing and increasing temperature on the mechanical properties of a rod made of steel 20X13 after normalization from 1000-1020 °C and tempering at 730-750 °C is shown in Table 3.

Table 3 - Mechanical properties of steel 20Х13 at low and elevated temperatures

Corrosion resistance of steel 20Х13

Steel 20Х13 is highly resistant to atmospheric conditions (except for the sea atmosphere), river and tap water.

Special properties of steel 20Х13

For parts operating at elevated temperatures for a long time, the maximum operating temperature is 450-475 °C, for short-term operation - 500-550 °C.

The density of steel 20Х13 is 7.76 g/cm3.

Heat treatment of welds of steel 20Х13

After welding, tempering of welded joints or products is carried out. The tempering temperature depends on the level of mechanical properties required. Tempering at 680-760 °C is most often used.

Technological parameters of steel 20Х13

Steel 20Х13 has good processability during hot plastic deformation. The temperature range of hot plastic deformation ranges from 1100 to 875-950 °C. Heating for rolling and forging to 780 °C is carried out slowly. After hot deformation, slow cooling is used.

For steel 20Х13, softening annealing is usually used at 750-800 °C with cooling in a furnace to 500 °C. Final heat treatment - hardening from 950-1000 °C with cooling in oil or air and tempering to a given hardness and corrosion resistance.

Subsequent release technology

As already indicated, to obtain the sorbitol structure, products made from 65G steel are subjected only to high tempering at temperatures of 550...600 °C, with cooling in still air. For particularly critical parts, an additional low holiday is sometimes carried out. Its temperature range is 160...200 °C, followed by slow cooling in air. This technology avoids the accumulation of thermal stresses in the product and increases its durability. For tempering, you can use not only flame, but also electric furnaces equipped with devices for forced air circulation. The holding time of products in such furnaces is from 110 to 160 minutes (increased time standards correspond to parts with complex configurations and large cross sections).

It is not recommended to use water and aqueous solutions of salts as working media when hardening 65G steel. The acceleration of the cooling process caused by water is often accompanied by uneven calcination.

The final quality control of hardening consists of assessing the macro- and microstructure of the metal, as well as determining the final hardness of the product. The surface hardness of products made from 65G steel should be within 35...40 HRC after normalization, and 40...45 HRC after quenching with high tempering.

40ХН2МА steel properties

σ4551/10000=686 MPa, σ4551/1000=137 MPa, σ5901/10000=13 MPa, σ5901/1000=29 MPa.

Mechanical properties of steel 40ХН2МА
GOST	Delivery condition, heat treatment mode	Section, mm	KP	σ0.2 (MPa)	σв(MPa)	δ5 (%)	ψ %	KCU (J/cm2)	NV, no more
GOST 4543-71	Bar. Hardening 850 °C, oil. Vacation 620 °C, water	25	—	930	1080	12	50	78	—
Bar. Hardening 850 °C, oil. Temperature 620 °C, oil.	25	—	835	980	12	55	98	—
GOST 8479-70	Forgings. Hardening. Vacation	500-800	440	440	635	11	30	39	197-235
300-500 500-800	490	490	655	12 11	35 30	49 39	212-248
100-300 300-500	540	540	685	13 12	40 35	49 44	223-362
100-300 300-500 500-800	590	590	735	13 12 10	40 35 30	49 44 39	235-277
100-300 300-500	640	640	785	12 11	38 33	49 44	248-293
100-300	685	685	835	12	38	49	262-311
Up to 100 100-300	735	735	880	13 12	40 35	59 49	277-321
Up to 100 100-300	785	785	930	12 11	40 35	59 49	293-331
Mechanical properties of steel 40ХН2МА depending on tempering temperature
Temperature, °C	σ0.2 (MPa)	σв(MPa)	δ5 (%)	ψ %	KCU (J/cm2)	HB
Hardening 850 °C, oil
200 300 400 500 600	1600 1470 1240 1080 860	1750 1600 1370 1170 960	10 10 12 15 20	50 50 52 59 62	59 49 59 88 147	525 475 420 350 275
Mechanical properties of steel 40ХН2МА at elevated temperatures
Test temperature, °C	σ0.2 (MPa)	σв(MPa)	δ5 (%)	ψ %	KCU (J/cm2)
Hardening 850 °C, oil. Vacation 580 °C.
20 250 400 500	950 830 770 680	1070 1010 950 700	16 13 17 18	58 47 63 80	78 109 84 54
Sample 5 mm in diameter, 25 mm long, rolled. Deformation speed 2 mm/min. Strain rate 0.001 1/s
700 800 900 100 1100 1200	— — — — — —	185 89 50 35 24 14	17 66 69 75 72 62	32 90 90 90 90 90	— — — — — —
Endurance limit of steel 40ХН2МА
σ-1, MPA	J-1, MÏÀ	n	Heat treatment
447 392 519	274 235	106	Section 100 mm. Hardening 850 °C, oil. Vacation 580 °C, σв=880 MPa. Section 400 mm. Hardening 850 °C, oil. Temperature 610 °C, σв=790 MPa, σ0.2=880 MPa, σв=1080 MPa
Impact strength of steel 40ХН2МА KCU , (J/cm2)
Т= +20 °С	Т= -40 °С	Т= -60 °С	Heat treatment
103	93	59	Hardening 860 °C, oil. Vacation 580 °C
Mechanical properties of steel 40ХН2МА depending on the section
Section, mm	Sample cutting location	σ0.2 (MPa)	σв(MPa)	δ4 (%)	ψ %	KCU (J/cm2)	HRCE
Bar. Hardening 850 °C, oil. Vacation 620 °C
40 60 80 100 120	Central Central 1/2R 1/2R 1/3R	880 830 730 670 630	1030 980 880 850 830	14 16 17 19 20	57 60 61 61 62	118 127 127 127 127	33 32 29 26 25
Hardening 850 °C, oil. Vacation 540-660 °C
up to 16 16-40 40-100 100-160 160-250	Ts ts ts ts	1000 900 800 700 650	1200-1400 1100-1300 1000-1200 900-1100 850-1000	9 10 11 12 12	— — — — —	90 50 60 60 60	— — — — —
Hardenability of steel 40ХН2МА
Distance from the end, mm	Note
1,5	3	6	9	12	15	21	27	33	42	Hardening 840 °C
49-59,5	40,5-60	50-60	50-59,5	49-59	48-59	45-56	41,5-53	41-50,5	36,5-48,5	Hardness for hardenability strips, HRC
Amount of martensite, %	Critical hardness, HRCе	Critical diameter in water	Critical diameter in oil
50 90	44-47 49-53	153 137-150	114 100-114
Physical properties of steel 40ХН2МА
T (Grad)	E 10-5 (MPa)	a 10 6 (1/Deg)	l (W/(m deg))	r (kg/m3)	C (J/(kg deg))	R 10 9 (Ohm m)
20	2.15	39	7850	331
100	2.11	11.6	38	490
200	2.01	12.1	37	506
300	1.9	12.7	37	522
400	1.77	13.2	35	536
500	1.73	13.6	33	565
600	13.9	31
700	29
800	27
Brief designations:
σв	— temporary tensile strength (tensile strength), MPa	å	— relative settlement at the appearance of the first crack, %
σ0.05	— elastic limit, MPa	Jê	— ultimate torsional strength, maximum shear stress, MPa
σ0.2	— conditional yield strength, MPa	σben	— ultimate bending strength, MPa
δ5,δ4,δ10	— relative elongation after rupture, %	σ-1	— endurance limit during bending test with a symmetrical loading cycle, MPa
σсж0.05 and σсж	— compressive yield strength, MPa	J-1	— endurance limit during torsion testing with a symmetrical loading cycle, MPa
ν	— relative shift, %	n	— number of loading cycles
sв	— short-term strength limit, MPa	R and ρ	— electrical resistivity, Ohm m
ψ	— relative narrowing, %	E	— normal modulus of elasticity, GPa
KCU and KCV	— impact strength, determined on a sample with concentrators of the types U and V, respectively, J/cm2	T	— temperature at which properties were obtained, degrees
sT	— proportionality limit (yield strength for permanent deformation), MPa	l and ë	— thermal conductivity coefficient (heat capacity of the material), W/(m °C)
HB	— Brinell hardness	C	- specific heat capacity of the material (range 20o - T), [J/(kg deg)]
H.V.	— Vickers hardness	pn and r	— density kg/m3
HRСе	— Rockwell hardness, scale C	A	— coefficient of thermal (linear) expansion (range 20o - T), 1/°С
HRB	— Rockwell hardness, scale B	σtТ	— long-term strength limit, MPa
HSD	- Shore hardness	G	— modulus of elasticity during torsional shear, GPa

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Spring steel 65G - characteristics, hardness, explanation

There are types of steels that have limited use. These include spring steel 65G. Its characteristics are distinguished by high elasticity parameters and wear resistance.

knives made of steel 65G

The photo shows a throwing knife “Twist” with an all-metal blade made of 65G steel

: Steel 5ХНМ - explanation, characteristics, GOST

Alloy composition

Minor additives include:

chromium, which increases the hardness of the material, the degree of its heat resistance is 0.25%;
nickel, which imparts anti-corrosion properties and ductility - up to 0.25%;
copper, increasing corrosion resistance – 0.20%;
sulfur and phosphorus – 0.035% each.

The last two elements refer to harmful impurities, the presence of which is inevitable. Phosphorus reduces the ductility of the alloy and increases its brittleness. Sulfur causes the phenomenon of red brittleness, that is, the appearance of cracks in the metal during intense heating. However, their concentration in the alloy does not exceed the value permissible for a high-quality material.

A small amount of alloying additives ensures that the alloy is relatively cheap, which makes it extremely popular. The chemical composition determines the physical and technological properties of 65G steel:

hardness at 20°C – 285 HB;
elastic modulus – 84 GPa;
high tensile strength – 750 MPa;
good impact strength – 3.0 – 3.5 kg*m/cm2;
specific gravity – 7850 kg/m3;
temperature range for hardening – 800 – 830°C;
forging temperature range – 760 – 1250°C.

Substitutes for the alloy can be the following brands:

55С2;
60С2А;
9ХС;
50HFA;
60С2;
70G;
55C.

Among the foreign analogues we can note:

G15660 - in the United States;
66Mn4 – Germany;
65Mn – China;
080A67 - Great Britain.

Heat treatment

Steel 65G, the characteristics of which are initially determined by its chemical composition, is subject to further heat treatment. In many ways, the quality of the products produced depends on it. As a result of thermal effects:

internal structural changes occur in the metal;
its mechanical properties are improved;
the wear resistance of products increases;
their reliability increases;
the cost of parts is reduced due to the use of cheaper additives;
The scope of product use is expanding.

The main stages of heat treatment are the following processes:

annealing;
further normalization;
hardening and tempering.

Hardening and tempering of products

Hardening occurs when a part is heated to temperatures above critical, and quickly cooled in a certain environment. The temperature range suitable for hardening parts made of 65G steel is 800 – 820°C. Further cooling is carried out in oil, which eliminates the possibility of cracking the surface of the products.

Depending on the characteristics specified by the operational requirements for products, when selecting a hardening mode, the following are taken into account:

heating equipment and method;
process temperature range;
exposure time in the selected mode;
type of quenching medium;
method of further cooling.

Annealing of products is carried out by reheating, after which holding and slow cooling procedures are carried out. The annealing temperature corresponds to the thermal effect during hardening of steel.

Tempering of the metal is carried out to eliminate internal stresses that appeared in it during the hardening process. At the output, the hardness of the alloy decreases somewhat, but its viscosity increases.

Tempering is carried out by secondary heating at a lower temperature and subsequent quiet cooling.

In addition, by changing the tempering temperature conditions, it is possible to impart different mechanical properties to the metal.

For products made from 65g steel, a high tempering option is usually carried out in the temperature range of 550 - 600 degrees with further cooling in air, but this reduces the impact strength.

For products requiring high reliability and durability, low tempering in the range of 160 - 200 ° C is additionally used, accompanied by slow cooling in air.

The output hardness of the steel can be 45 – 47 HRC.

Advantages and disadvantages

Undoubtedly, the wide range of applications is due to the obvious advantages that 65G steel has:

characteristics and use for knives are determined by resistance to impact deformation and ease of sharpening;
high hardness, up to 50-55 HRC, protects products from breakage;
low cost makes it possible to reduce the cost of manufactured products;
high tensile strength makes it indispensable in the manufacture of spring products;
a significant yield strength allows the product to restore its shape after the deforming load ceases;
metal lends itself well to forging;
After the blackening procedure, an oxide film is formed on its surface, protecting the surface from corrosion.

Like any alloy, 65G steel has certain disadvantages:

it is highly susceptible to corrosion;
despite easy sharpening, finishing the cutting edge is too labor-intensive;
there is a possibility of deformation under shock loads.

Application area

The alloy is a structural material with a high degree of elasticity, which allows it to be used in mechanical engineering and machine tool manufacturing for the production of mechanisms operating under long-term loads:

for creating springs in cars;
thrust washers and slates;
bearings and brake bands;
spring mechanisms;
friction discs.

The following can also be made from steel grades 65 and 70:

sports blades;
throwing knives;
medical products;
razors;
other elements not subject to prolonged shock loads.

The material is not suitable for welding and use in conditions of high humidity, as it is susceptible to corrosion. However, it can be used in resistance spot welding operations. Products made from it must be lubricated with oil or used only in a dry room.

Description of steel grade 65g

65 is the carbon content in the alloys in hundredths, and “g” is manganese (the alloying element).

Steel forging temperature: start - 1250 °C, end - 760−780°C.

65 g is a wear-resistant, tough, durable, elastic material with good tear resistance and shock resistance.

Mechanical properties of steel - the following categories:

3;
3a;
3b;
3c;
3 g;
4;
4a;
4b.

Quenching temperature - 830 °C, oil. Temperature: 470°C.

There are several types of supply of 65 g steel, one of them is the following:

General information about steel 65g

This steel is very popular due to its relatively low cost . It belongs to the spring-spring type and passes the bluing and blackening procedures very well.

Due to its characteristics, it is used to make throwing knives; it is extremely rarely used to create cutting knives.

This is due to the fact that such steel oxidizes extremely quickly and becomes rusty.

If we talk about hardening, then this material is not afraid of overheating. However, if the temperatures are high enough, the toughness decreases quite quickly, which in turn inevitably leads to large grain growth in the fine texture of the fibers.

The hardening temperature can be different (from 800 to 820 degrees Celsius). It all depends on the complexity of the outline of the original product and the metal characteristics required for a particular use scenario.

Due to the addition of Manganese, such an alloy is also called deoxidized steel; this applies to absolutely all materials containing such a component. Knives acquire their properties in cases where pearlite transformation has been achieved during the hardening process.

Chemical composition in % of material 65G

C	Si	Mn	Ni	S	P	Cr	Cu
0.62 — 0.7	0.17 — 0.37	0.9 — 1.2	up to 0.25	up to 0.035	up to 0.035	up to 0.25	up to 0.2

Mechanical properties:

sв	— Short-term strength limit,
sT	— Limit of proportionality (yield strength for permanent deformation),
d5	— Elongation at break,
y	— Relative narrowing,
KCU	— Impact strength,
HB	— Brinell hardness,

Physical properties:

T	— Temperature at which these properties were obtained,
E	— Modulus of elasticity of the first kind,
a	— Coefficient of thermal (linear) expansion (range 20° - T),
l	— Thermal conductivity coefficient (heat capacity of the material),
r	— Density of the material,
C	— Specific heat capacity of the material (range 20° - T ),
R	— Electrical resistivity,

Magnetic properties:

Hc	— Coercive force (no more),
Umax	— Magnetic permeability (no more),
P1.0/50	— Specific losses (no more) at magnetic induction 1.0 T and frequency 50 Hz,
B100	— Magnetic induction Tl (not less) in magnetic fields at a magnetic field strength of 100,

Weldability:

no limits	— welding is performed without heating and without subsequent heat treatment
limited weldability	— welding is possible when heated to 100-120 degrees. and subsequent heat treatment
difficult to weld	— to obtain high-quality welded joints, additional operations are required: heating to 200-300 degrees. during welding, heat treatment after welding

Characteristics of steel (briefly)

Wear resistance
Viscosity
Strength
Elasticity
Tear resistance
Impact resistance
The knives show a good cut (although this is of no use for throwing knives)
Relatively low cost

Technological properties of material 65G

Weldability:	not applicable for welded structures
Flock Sensitivity:	insensitive
Tendency to temper brittleness:	inclined

Steel for tournament weapons

All of the above is relevant not only for the manufacture of throwing knives, but also for the production of tournament weapons (swords, checkers, etc.).

In the photo: Tournament weapons for the “Heroic Fun” festival in the Oruzheynik park (Zlatoust) were made from 65G steel.

: Steel 65X13 for knives - characteristics, application

Peculiarities

Due to its properties, 65g steel is not suitable for welding. But it is worth noting that the range of uses is quite wide, even if you do not take into account edged weapons. Various springs, springs, bearing housings, components and metal structures are made from it. It has found application even in trucks - this particular material is used to create rear axle springs.

In order for the material to retain its properties and not become rusty, it must be kept in a dry room, and the products must be periodically coated with oil.

Due to its low cost and fairly decent properties, 65g steel is used as analogues of such materials as: 55С2, 60С2, 70, 70Г, У8А, 9Хс.

The elasticity of the metal during forging allows you to make edged weapons and blades at home. It is for this reason that 65g steel has become widespread in this industry. This applies to manual production not only of sports equipment or tools for reconstruction, but also for domestic use - in the kitchen.

Minuses

As noted above, steel belongs to the carbon group and is susceptible to corrosion. Therefore, do not forget two important rules: keep the blades dry and clean and periodically lubricate them with castor oil. Caring for knives made from 65G steel is comparable to caring for knives made from Damascus steel.

Heat treatment modes

The temperature range for hardening steel 65G is in the range of 800-830 °C. Subsequent high tempering at 160-200 °C with further cooling in still air makes it possible to obtain a steel hardness of 45-47 HRC. This grade of steel is not afraid of overheating, however, when hardened at high temperatures, the impact strength of the steel begins to decrease.