GOST 18968-73

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  ГОСТ 18968-73

GOST 18968−73 Rods and strip made of corrosion-resistant high-temperature steel for steam turbine blades. Technical specifications (with Changes 1−5 N)

GOST 18968−73

Group В32

INTERSTATE STANDARD

RODS AND STRIPS OF CORROSION-RESISTING AND HEAT RESISTING STEELS FOR STEAM TURBINE BLADES

Specifications

Corrosion-resistant and heat-proof steel bars and strips for steam turbine blades. Specifications

ISS 77.140.60
OKP 09 6001

Date of introduction 1974−01−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of heavy, power and transport machine building of the USSR

2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from 29.07.73 G. N 1643

3. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

The designation of the reference document referenced	Item number
GOST 1133−71	1.1
GOST 1497−84	4.7
GOST 2590−88	1.1
GOST 2591−88	1.1
GOST 4405−75	1.2; 1.3
GOST 5632−72	2.1
GOST 5949−75	2.3; 2.9
GOST 7564−97	4.6
GOST 7566−94	3.2; 3.5; 5.1
GOST 9012−59	4.9
GOST 9454−78	4.8
GOST 10243−75	4.4
GOST 12344−2003	4.1
GOST 12345−2001	4.1
GOST 12346−78	4.1
GOST 12347−77	4.1
GOST 12348−78	4.1
GOST 12349−83	4.1
GOST 12350−78	4.1
GOST 12351−2003	4.1
GOST 12352−81	4.1
GOST 12353−78	4.1
GOST 12354−81	4.1
GOST 12355−78	4.1
GOST 12356−81	4.1
GOST 12357−84	4.1
GOST 12358−2002	4.1
GOST 12359−99	4.1
GOST 12360−82	4.1
GOST 12361−2002	4.1
GOST 12362−79	4.1
GOST 12363−79	4.1
GOST 12364−84	4.1
GOST 12365−84	4.1
GOST 14019−2003	4.10
GOST 21120−75	2.4; 4.5

4. Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

5. EDITION Changes N 1, 2, 3, 4, 5, approved in March 1976, December 1978, January 1983, June 1988, June 1990 (IUS 4−76, 1−79, 5−83, 10−88, 9−90)


This standard applies to hot rolled and forged round and square rods and strips of corrosion resistant and heat resistant steel for steam turbine blades operating at temperatures up to 580 °C.

1. ASSORTMENT

1.1. Shape, dimensions and limit deviations of bars and strips shall comply with:

hot rolled round bars with diameter up to 150 mm — GOST 2590;

hot rolled bars in square from, square to 100 mm — GOST 2591;

square bars hot-rolled from a side of the square from 100 mm to 200 mm — normative-technical documentation.

of bars round and square forged — GOST 1133.

(Changed edition, Rev. N 5).

1.2. Dimensions and limit deviations of hot-rolled strips shall be as specified in table.1, the dimensions of wrought-iron bands — table.1 and GOST 4405.

Maximum deviations forged strips should comply with GOST 4405; maximum deviations of wrought iron strips, not specified in GOST 4405 are the closest larger size, GOST 4405.

Table 1

mm

Thickness		Width
Nomin.	Pred. off.	Nomin.	Pred. off.
8	+0,5	40	+1,8
8	+0,5	125	+2,6
10	+0,6	40	+1,8
12	+0,6	16	+1,0
12	+0,6	65	+2,6
14	+0,6	35	+1,8
14	+0,6	65	+2,6
16	+0,8	20	+1,0
16	+0,8	25	+1,3
16	+0,8	35	+1,8
16	+0,8	40	+1,8
16	+0,8	45	+2,0
16	+0,8	55	+2,2
16	+0,8	65	+2,6
18	+0,8	Thirty five	+1,8
18	+0,8	45	+2,0
18	+0,8	60	+2,2
20	+0,8	22	+1,3
20	+0,8	25	+1,3
20	+0,8	30	+1,3
20	+0,8	35	+1,8
20	+0,8	40	+1,8
20	+0,8	45	+2,0
20	+0,8	50	+2,0
20	+0,8	60	+2,2
20	+0,8	70	+2,6
20	+1,0	80	+2,6
20	+1,0	90	+2,6
20	+1,0	100	+2,6
22	+1,0	50	+2,0
22	+1,2	80	+2,6
22	+1,2	95	+2,6
22	+1,2	120	+2,6
22	+1,2	125	+2,6
25	+1,0	30	+1,3
25	+1,0	35	+1,8
25	+1,0	40	+1,8
25	+1,0	45	+2,0
25	+1,0	50	+2,0
25	+1,0	55	+2,0
25	+1,0	60	+2,2
25	+1,0	65	+2,6
25	+1,2	70	+2,6
25	+1,2	75	+2,6
25	+1,2	80	+2,6
25	+1,2	85	+2,6
25	+1,2	120	+2,6
25	+1,2	125	+2,6
30	+1,2	35	+1,8
30	+1,2	40	+1,8
30	+1,2	45	+2,0
30	+1,2	50	+2,0
30	+1,2	55	+2,2
30	+1,2	60	+2,2
30	+1,2	65	+2,6
30	+1,2	70	+2,6
30	+1,2	75	+2,6
30	+1,2	80	+2,6
30	+1,2	90	+2,6
30	+1,2	100	+2,6
30	+1,2	110	+2,6
30	+1,2	120	+2,6
30	+1,2	125	+2,6
30	+1,2	130	+2,6
30	+1,2	150	+2,6
30	+1,2	180	+2,6
35	+1,2	40	+1,8
35	+1,2	45	+2,0
35	+1,2	50	+2,0
35	+1,2	55	+2,2
35	+1,2	60	+2,2
35	+1,3	65	+2,6
35	+1,3	70	+2,6
35	+1,3	75	+2,6
35	+1,3	80	+2,6
35	+1,3	90	+2,6
35	+1,3	100	+2,6
35	+1,3	110	+2,6
35	+1,3	120	+2,6
35	+1,3	130	+2,6
40	+2,0	50	+2,0
40	+2,0	55	+2,2
40	+2,0	60	+2,2
Forty	+2,0	65	+2,6
40	+2,0	70	+2,6
40	+2,0	75	+2,6
40	+2,0	80	+2,6
40	+2,0	90	+2,6
40	+2,0	100	+2,6
40	+2,0	110	+2,6
40	+2,0	130	+2,6
45	+2,0	50	+2,0
45	+2,0	55	+2,2
45	+2,0	60	+2,2
45	+2,0	70	+2,6
45	+2,0	75	+2,6
45	+2,0	80	+2,6
45	+2,0	90	+2,6
45	+2,0	100	+2,6
45	+2,0	110	+2,6
45	+2,0	120	+2,6
45	+2,0	130	+2,6
45	+2,0	140	+2,6
45	+2,0	180	+2,6
50	+2,0	55	+2,2
50	+2,0	60	+2,2
50	+2,0	65	+2,6
50	+2,0	70	+2,6
50	+2,0	80	+2,6
50	+2,0	90	+2,6
50	+2,0	100	+2,6
50	+2,0	110	+2,6
50	+2,0	120	+2,6
50	+2,0	130	+2,6
50	+2,0	140	+2,6
50	+2,0	180	+2,6
55	+2,0	60	+2,2
55	+2,0	70	+2,6
55	+2,0	75	+2,6
55	+2,0	90	+2,6
55	+2,0	100	+2,6
55	+2,0	110	+2,6
55	+2,0	130	+2,6
55	+2,0	140	+2,6
55	+2,0	180	+2,6
60	+2,0	65	+2,6
60	+2,0	70	+2,6
60	+2,0	90	+2,6
60	+2,0	100	+2,6
60	+2,0	110	+2,6
60	+2,0	120	+2,6
60	+2,0	130	+2,6
60	+2,0	180	+2,6
60	+2,0	200	+2,6
65	+2,0	80	+2,6
65	+2,0	100	+2,6
65	+2,0	110	+2,6
65	+2,0	140	+2,6
65	+2,0	180	+2,6
70	+2,0	90	+2,6
70	+2,0	120	+2,6
70	+2,0	150	+2,6
70	+2,0	170	+2,6
70	+2,0	180	+2,6
75	+2,0	80	+2,6
75	+2,0	90	+2,6
75	+2,0	125	+2,6
75	+2,0	160	+2,6
75	+2,0	190	+2,6
80	+2,0	125	+2,6
80	+2,0	150	+2,6

Note. By agreement between manufacturer and consumer produce strips of a width over 200 mm with a thickness of 60 mm or more; thickness more than 80 mm with a width of 100 mm and more.

1.3. The length of hot rolled and forged bars — according to GOST 4405.

1.2, 1.3. (Changed edition, Rev. N 2).

1.4. Length of bars and stripes made with a full heat treatment (hardening+tempering, normalizing, quenching from rolling heat+tempering) shall be not less than 1.0 m.

1.5. At the request of the consumer made rods and strips with a length multiple of the length of the blanks blades.

(Changed edition, Rev. N 3).

1.6. Stripes are made with blunt corners.

1.7. Assortment of bars and strips, manufactured from metal vacuum-arc remelting and vacuum induction melting, by agreement between manufacturer and user.

(Changed edition, Rev. N 3).

2. TECHNICAL REQUIREMENTS

2.1 a. The rods and strips are manufactured in accordance with the requirements of this standard for technological regulations approved in the prescribed manner.

(Added, Rev. N 3).

2.1. The bars and strips are made from steel grades: 08KH13 (0Х13), 08KH13-sh, 12H13 (1Х13), 12H13-sh, 20X13 (2X13), 20X13-sh, 15KH11MF (1Х11МФ), 15KH11MF-sh, 15KH12VNMF (1Х12ВНМФ, ЭИ802), 15KH12VNMF-sh, 20KH12VNMF (2Х12ВНМФ, ЭП428), 20KH12VNMF-sh, 18KH11MNFB (2Х11МФБН, ЭП291), 18KH11MNFB-W with the chemical composition according to GOST 5632.

Note. On demand of the consumer steel of these brands are made by vacuum arc remelting and vacuum induction smelting.

2.2. At customer’s request, rods and strips are made:

without heat treatment;

in the annealed condition;

full heat treatment (hardening+tempering, normalizing, quenching from rolling heat+tempering) square bars and strips steel grades 12H13 (1Х13), 12H13-sh and 20X13 (2X13), 20X13-sh size up to 100 mm.

Note. The production of round rods of steel all brands, square bars and strips of steel grades: 08KH13 (0Х13), 08KH13-sh, 15KH11MF (1Х11МФ), 15KH11MF-sh, 15KH12VNMF (1Х12ВНМФ, ЭИ802), 15KH12VNMF-sh, 20KH12VNMF, (2Х12ВНМФ, ЭП428), 20KH12VNMF-sh, 18KH11MNFB (2Х11МФБН, ЭП291), 18KH11MNFB-W full heat treatment is performed in agreement between manufacturer and consumer.

2.1, 2.2. (Changed edition, Rev. N 3).

2.3. The state of the surface and macrostructure of hot rolled and forged bars and strips shall conform to the requirements of GOST 5949.

Note. Stated in the order, or the subsequent hot machining.

2.4. Quality rods, strips, intermediate the workpiece when carrying out ultrasonic inspection (UT) should match 1 group, GOST 21120.

(Changed edition, Rev. N 4).

2.5. By agreement between manufacturer and consumer rods and strips is subjected to etching with subsequent Stripping.

2.6. Bars and strips, sliced on presses and shears, may have crumpled ends. At the request of the consumer burrs on the ends must be stripped.

(Changed edition, Rev. N 4).

2.7. Mechanical properties of steel at 20 °C, determined by the longitudinal heat-treated samples or samples made from heat-treated blanks, must conform to the standards specified in table.2.

Table 2

Steel grade	Yield strength , N/mm(kgf/mm)	Times — ing resistance, N/mm(kgf/mm)	Regarding elongation , %	Regarding contraction, %	Impact toughness KCV, j/cm(kgf·m/cm)	Hardness
						Indentation diameter, mm	The number of hardness HB
		not less than
08KH13, 08KH13-SH	Not less than 410 (42)	580 (60)	20	60	98 (10)	4,4−4,1	187−217
12H13, 12H13-SH	440−610 (45−62)	620 (63)	20	60	78 (8)	4,35−4,0	192−229
	540−705 (55−72)	670 (68)	16	60	59 (6)	Of 4.20 to 3.90	207−241
20X13, 20X13-SH	490−655 (50−67)	670 (68)	18	50	69 (7)	4.2 ñ 3.9	207−241
15KH11MF, 15KH11MF-SH	590−755 (60−77)	740 (75)	15	50	59 (6)	4,0−3,7	Are 229−269
15KH12VNMF (ЭИ802), 15KH12VNMF-SH	590−735 (60−75)
20KH12VNMF (ЭП428), 20KH12VNMF-SH	590−755 (60−77)
18KH11MNFB (EP 291), 18KH11MNFB-SH	590−735 (60−75)

Notes:

1. Are given in table.2 rules apply to bars and stripes a diameter or thickness up to 60 mm When the test bars and strips of a diameter or thickness of 61−100 mm is allowed for lower values of elongation at 1% and narrowing by 5% in absolute values and decreasing impact strength of 5 j/cm(0.5 kgf·m/cm) at the rate of at least 78 j/cm(8 kgf·m/cm) and 10 j/cm(1 kgf·m/cm) at the rate of 78 j/cm(8 kgf·m/cm) or more. Mechanical properties of bars and strips of a diameter or thickness greater than 100 mm define the workpiece diameter or thickness of 90−100 mm.

2. Norms of mechanical properties of rods and strips, made of metal vacuum-arc remelting and vacuum induction melting, established by agreement between manufacturer and consumer.

3. The bars and strips of steel 12H13, 12H13-W with yield stress 540−705 N/mm(55−72 kg/mm) are supplied by agreement between manufacturer and consumer. Norms of mechanical properties are not looking to 01.01.94, the test results are entered into the document of quality. When not recording in order the bars and strips of steel 12H13, 12H13-sh manufactured with the norms of mechanical properties for a category of strength with a yield strength 440−610 N/mm(45−62 kg/mm).

4. By agreement with the consumer allowed the production of rods with full heat treatment without limitation of the upper value of the yield stress.

5. In the manufacture of bars and strips without heat treatment and annealed in agreement with the consumer allowed to set higher standards for the lower limit on the relative elongation, relative narrowing and toughness.


The recommended heat treatment of the samples and blanks for determination of mechanical properties, as well as bars and bands is given in the Appendix.

(Changed edition, Rev. N 4, 5).

2.8. Bars and strips of a diameter less than 16 mm and of a thickness less than 12 mm, made of steel 12H13 (1Х13), 12H13-sh and 20X13 (2X13), 20X13-W full heat treatment, instead of testing the relative narrowing and toughness is subjected to bending test through 180° in a cold state. The bending point should be no signs of cracks, tears and bundles.

(Changed edition, Rev. N 3, 4).

2.9. For bars and strip in the annealed condition of the steel 08KH13 (0Х13), 08KH13-sh, 12H13, (1Х13), 12H13-sh, 20X13 (2X13), 20X13-sh hardness norms are accepted by GOST 5949.

For bars and strips of steel grades 15KH11MF (1Х11МФ), 15KH11MF-sh, 20KH12VNMF (2Х12ВНМФ, ЭП428), 20KH12VNMF-sh, 18KH11MNFB (2Х11МФБН, ЭП291), 18KH11MNFB-sh hardness number should be no more than 229 HB, indentation diameter not less than 4.0 mm.

2.10. For bars and strips with a length more than 500 mm after heat treatment hardness is determined on both ends of the rod and the strip. The difference in the hardness values on one workpiece must not exceed 30 HB.

2.11. The degree of infestation volosovichi identified on the surfaces of the magnetic method or by etching, should not exceed the limits specified in table.3.

Table 3

The total area of the controlled surface, cm	The maximum length of wooloowin, mm	Open smelting		Electroslag remelting
		The number of wooloowin.	The total length of wooloowin, mm	The number of wooloowin.	The total length of wooloowin, mm
Up to 50	3	2	5	1	2
51−200	4	4	10	1	4
201−400	5	8	20	2	6
401−800	6	10	40	2	14
801−1200	7	12	50	3	18
1201−2000	8	16	70	4	24
2001−3000	8	20	90	5	30
3001−4000	10	24	110	6	36
4001−8000	10	28	130	7	42

Notes:

1. For every subsequent 200 cmcontrolled surface finished parts made from an open metal smelting, and 500 cmcontrolled surface of parts made of metal of electroslag remelting, the area of which exceeds 8000 cmallowed additional not more than one volosovichi length up to 5 mm.

2. On the details area of 200 cmor more, made of an open metal smelting, on separate sites of a surface area of 10 cmis not allowed the accumulation of more than five wooloowin, on the details area of 200 cmor more, made of metal of electroslag remelting, on separate sites of a surface area of 10 cmis not allowed the accumulation of more than three wooloowin.

3. Volosovichi located in one line with spaces between them of less than 2 mm, are continuous.


(Changed edition, Rev. N 2).

3. ACCEPTANCE RULES

3.1. (Deleted, Rev. N 3).

3.2. Bars and stripes take the parties consisting of one steel smelting, one size and one mode of heat treatment.

For electroslag and vacuum-arc melting ingots are smelted from a single source of melting. Each batch is accompanied by a quality document with GOST 7566.

(Changed edition, Rev. N 3).

3.3. To check the quality of steel from the party of bars and stripes are selected:

a) for chemical analysis — one sample from melting ladle-or single rod;

b) for quality control of surfaces and sizes — all the bars and strips;

C) to control the macrostructure of two rods or two bands;

g) when verification of the impact of internal defects in rods, strips and of the intermediate workpiece is subjected to continuous control;

d) to determine the mechanical properties of the two rods or two bands (for bars and strips with full heat treatment — from rod or strip with the highest and lowest hardness value);

e) to test the hardness of the annealed bars and stripes — 2% of batch but not less than two rods or bars; for bars and strips with full heat treatment — 100% of bars and bands.

(Changed edition, Rev. N 3, 4).

3.4. On-demand user control of mechanical properties is carried out at twice the number of bars or strips.

(Changed edition, Rev. N 3).

3.5. Re-testing — GOST 7566.

(Added, Rev. N 3).

4. TEST METHODS

4.1. Chemical composition of steel is determined according to GOST 12344 — GOST 12365 or other methods of equal accuracy standard.

In case of disagreement between the manufacturer and user of chemical analysis carried out according to specified standards.

(Changed edition, Rev. N 4, 5).

4.2. The dimensions of bars and stripes test a measuring instrument corresponding accuracy.

4.3. The surface quality test without the use of magnifying devices. If necessary, the surface is sanded with a file or abrasive wheel and etched.

4.4. Control of macrostructure of steel is carried out according to GOST 10243 on two templeto from different bars and bands.

(Changed edition, Rev. N 3).

4.5. Ultrasonic inspection of bars, bands, the intermediate workpiece held in the churchyard 21120.

(Changed edition, Rev. N 4).

4.6. Sampling for mechanical tests according to GOST 7564.

Mechanical properties determine:

a) for bars and strips without heat treatment or annealed samples are made from pieces with a diameter of 20−25 mm after full heat treatment. In the section of the bars and strips of less than 25 mm is subjected to a heat treatment of the samples taken from the finished profile;

b) for bars and strips with a full heat treatment on the samples taken from the heat treated bars and bands.

4.7. The tensile test is carried out according to GOST 1497.

4.8. Test for impact strength at 20 °C is performed according to GOST 9454 on samples of type I.

4.9. Brinell hardness number is determined according to GOST 9012.

(Changed edition, Rev. N 3).

4.10. The test is carried out cold bending around a mandrel with a diameter equal to two thickness of the sample according to GOST 14019.

4.11. The main method of control components for the presence of wooloowin is the method of magnetic flaw detection. Allowed other testing methods.

4.12. Bars and strips of a thickness of 80 mm and subjected to ultrasonic inspection in the finished rolled products. Bars and strips of a thickness up to 80 mm are UT on the manufacturers in the intermediate workpiece, or supply a profile.

(Changed edition, Rev. N 4, 5).

5. PACKING, MARKING, TRANSPORTATION AND STORAGE

5.1. Packing, marking, transportation and storage — by GOST 7566.

5.2. Bars and stripes, made of steel produced by electroslag remelting, in addition branded with the letter «W», vacuum arc remelting the letters «VD», vacuum-induction melting — with the letters «VI».

5.1, 5.2. (Changed edition, Rev. N 3).

APPLICATION (recommended). THE MODE OF HEAT TREATMENT AND COOLING MEDIUM

APP
Recommended

View heat treatment	The mode of heat treatment steel grades
	08KH13 (0Х13)	12H13 (1Х13)	20X13 (2X13)	15KH11MF (1Х11МФ)	15KH12VNMF (1Х12ВНМФ, ЭИ802)	20KH12VNMF (2Х12ВНМФ, ЭП428)	18KH11MNFB (2Х11МФБН, ЭП291)
Normalization or quenching	1000 °C — 1050 °C; water	1000 °C — 1050 °C; the air or oil	1000 °C — 1050 °C; the air or oil	1050 °C — 1100 °C; the air or oil	1010 °C To 1060 °C, oil	1010 °C To 1060 °C, oil	1080 °C — 1130 °C, air or oil
Vacation	660 °C — 770 °C; the air	660 °C — 770 °C; the air	660 °C — 770 °C; the air	660 °C — 770 °C; the air	660 °C — 770 °C; the air	660 °C — 770 °C; the air	660 °C — 770 °C; the air