GOST 11447-80 Locking Studs for Py Over 10 to 100 MPa

Locking studs for Py over 10 to 100 MPa (over 100 to 1000 kgf/cm²)

SPECIFICATIONS

INTERSTATE STANDARD

LOCKING STUDS FOR Py OVER 10 TO 100 MPa (OVER 100 TO 1000 kgf/cm²) Technical requirements Locking studs for Py10 - 100 MPa (100 - 1000 kgf/cm²). Technical requirements	GOST 11447-80

Effective date 01.01.82

This standard applies to locking studs used for flange joints of valves and pipeline connecting parts used in the chemical and petrochemical industries at Py over 10 to 100 MPa (over 100 to 1000 kgf/cm²), at temperatures from minus 50 to plus 510 °C.

The requirements of Sections 2, 3, 4; Clauses 1.1, 1.2, 5.1, 5.2, 5.4, 5.6, 5.8 are mandatory; other requirements of this standard are recommended.

(Revised edition, Amendment No. 2).

1. DESIGN AND DIMENSIONS

1.1. Studs are manufactured in two types:

A — with identical nominal diameters of the thread and the plain section;

B — with the nominal thread diameter larger than the nominal diameter of the plain section.

For use at temperatures above 200 °C, only type B studs are manufactured.

1.2. The design and dimensions of the studs shall comply with those shown in the drawing and in Table 1.

Table 1

mm

Nominal thread diameter d	Diameter of the plain section d₁h12	Diameter of the shank d₂	Length of the screwed-in threaded end l₁		Length of the threaded end l₂		Length of the shank l₃		Length of the shank l₄	Width across flats S		Undercut radius R	Chamfer C	Stud length limit (excluding the screwed-in end
			nom.	tolerance	nom.	tolerance	nom.	tolerance		nom.	tolerance
12	9.5	8	17	+0.52	30	±1.5	7	+0.20	8	7	-0.20	4	1.0	30-80
14	11.0	10	20				9			8			1.6	35-90
16	13.0	12	22				10	+0.24		10			2.0	40-100
20	16.0	15	28	+0.62	36		13			12	-0.24		3.0	45-110
22	18.0	17	30		40					14				50-120
24	19.0		33		45							6		60-130
27	22.0	20	35				15			17			4.0	70-140
30	24.0	22	40		55		16			19	-0.28			80-160
33	27.0	25	45	+0.74						22				90-180
36	29.0	27	50		60	±2.0	20	+0.28	10	24		8	6.0	100-200
39	32.0	30	52		65				12	27				120-220
42	35.0	32	58		70		22		14	30				130-230
45	38.0	35	61		75		24			32	-0.34	10	7.0	140-240
48	40.0	37	64		80		26		15					150-250
52	44.0	41	70		85		28		18	36		12	8.0	160-260

Examples of designations for a type A stud with thread diameter d=20 mm, stud length l=50 mm, made of steel grade 40KhFA, without coating:

Stud AM20×50.40KhFA GOST 11447-80

Same, type B:

Stud BM20×50.40KhFA GOST 11447-80

Same, type A, with coating 02, thickness 9 µm:

Stud AM20×50.40KhFA, 029 GOST 11447-80

Same, type B:

Stud BM20×50.40KhFA, 029 GOST 11447-80

1.3. The mass of type A studs shall comply with that specified in Table 2, and of type B studs — in Table 3.

Table 2

Stud length, l, mm	Nominal thread diameter, d, mm
	12	14	16	20	22	24	27	30	33	36	39	42	45	48	52
	Weight, kg
30	0.040	-	-	-	-	-	-	-	-	-	-	-	-	-	-
35	0.044	0.064	-	-	-	-	-	-	-	-	-	-	-	-	-
40	0.049	0.070	0.097	-	-	-	-	-	-	-	-	-	-	-	-
45	0.053	0.076	0.105	0.174	-	-	-	-	-	-	-	-	-	-	-
50	0.057	0.082	0.113	0.187	0.238	-	-	-	-	-	-	-	-	-	-
55	0.060	0.089	0.121	0.199	0.252	-	-	-	-	-	-	-	-	-	-
60	0.066	0.095	0.128	0.211	0.267	0.332	-	-	-	-	-	-	-	-	-
65	0.071	0.101	0.136	0.224	0.282	0.350	-	-	-	-	-	-	-	-	-
70	0.075	0.107	0.144	0.236	0.297	0.368	0.477	-	-	-	-	-	-	-	-
75	0.080	0.113	0.152	0.248	0.312	0.386	0.499	-	-	-	-	-	-	-	-
80	-	0.125	0.168	0.273	0.342	0.421	0.544	0.685	-	-	-	-	-	-	-
85	-	0.125	0.168	0.273	0.342	0.421	0.544	0.685	-	-	-	-	-	-	-
90	-	0.131	0.176	0.285	0.357	0.439	0.567	0.713	0.900	-	-	-	-	-	-
95	-	-	0.184	0.298	0.372	0.457	0.589	0.741	0.934	-	-	-	-	-	-
100	-	-	0.192	0.310	0.387	0.475	0.612	0.786	0.967	1.167	-	-	-	-	-
105	-	-	-	0.322	0.402	0.492	0.634	0.796	1.001	1.207	-	-	-	-	-
110	-	-	-	0.335	0.417	0.510	0.657	0.824	1.034	1.247	-	-	-	-	-
115	-	-	-	-	0.431	0.528	0.679	0.852	1.068	1.287	-	-	-	-	-
120	-	-	-	-	0.446	0.546	0.702	0.879	1.101	1.327	1.662	-	-	-	-
130	-	-	-	-	-	0.581	0.747	0.935	1.169	1.409	1.756	2.063	-	-	-
140	-	-	-	-	-	-	0.792	0.990	1.236	1.487	1.850	2.172	2.574	-	-
150	-	-	-	-	-	-	-	1.046	1.303	1.567	1.940	2.201	2.699	3.113	-
160	-	-	-	-	-	-	-	1.101	1.370	1.647	2.037	2.389	2.824	3.255	3.921
170	-	-	-	-	-	-	-	-	1.437	1.727	2.131	2.498	2.948	3.397	4.088
180	-	-	-	-	-	-	-	-	1.504	1.806	2.225	2.607	3.073	3.539	4.255
190	-	-	-	-	-	-	-	-	-	1.886	2.318	2.716	3.198	3.681	4.421
200	-	-	-	-	-	-	-	-	-	1.966	2.412	2.824	3.323	3.823	4.588
210	-	-	-	-	-	-	-	-	-	-	2.506	2.939	3.448	3.965	4.755
220	-	-	-	-	-	-	-	-	-	-	2.600	3.042	3.573	4.107	4.821
230	-	-	-	-	-	-	-	-	-	-	-	3.151	3.697	4.250	5.088
240	-	-	-	-	-	-	-	-	-	-	-	-	3.822	4.392	5.255
250	-	-	-	-	-	-	-	-	-	-	-	-	-	4.534	5.422
260	-	-	-	-	-	-	-	-	-	-	-	-	-	-	5.588

Table 3

Stud length l, mm	Nominal thread diameter d, mm
	12	14	16	20	22	24	27	30	33	36	39	42	45	48	52
	Mass, kg, max
30	0.037	-	-	-	-	-	-	-	-	-	-	-	-	-	-
35	0.039	0.059	-	-	-	-	-	-	-	-	-		-	-	-
40	0.042	0.063	0.090	-	-	-	-	-	-	-	-	-	-	-	-
45	0.045	0.067	0.095	0.164	-	-	-	-	-	-	-	-	-	-	-
50	0.048	0.071	0.100	0.173	0.224	-	-	-	-	-	-	-	-	-	-
55	0.051	0.075	0.105	0.181	0.235	-	-	-	-	-	-	-	-	-	-
60	0.054	0.078	0.110	0.189	0.245	0.306	-	-	-	-	-	-	-	-	-
65	0.057	0.082	0.115	0.198	0.256	0.318	-	-	-	-	-	-	-	-	-
70	0.059	0.086	0.121	0.206	0.266	0.329	0.436	-	-	-	-	-	-	-	-
75	0.062	0.090	0.126	0.214	0.277	0.341	0.452	-	-	-	-	-	-	-	-
80	0.065	0.094	0.131	0.222	0.287	0.353	0.468	0.597	-	-	-	-	-	-	-
85	-	0.098	0.136	0.231	0.298	0.364	0.483	0.615	-	-	-	-	-	-	-
90	-	0.102	0.141	0.239	0.308	0.376	0.499	0.633	0.808	-	-	-	-	-	-
95	-	-	0.146	0.247	0.319	0.388	0.514	0.651	0.830	-	-	-	-	-	-
100	-	-	0.151	0.256	0.330	0.400	0.520	0.668	0.852	1.055	-	-	-	-	-
105	-	-	-	0.264	0.340	0.411	0.546	0.686	0.875	1.082	-	-	-	-	-
110	-	-	-	0.272	0.351	0.423	0.561	0.704	0.897	1.110	-	-	-	-	-
115	-	-	-	-	0.361	0.435	0.577	0.722	0.920	1.138	-	-	-	-	-
120	-	-	-	-	0.372	0.447	0.592	0.739	0.942	1.166	1.483	-	-	-	-
130	-	-	-	-	-	0.470	0.624	0.775	0.987	1.221	1.548	1.841	-	-	-
140	-	-	-	-	-	-	0.655	0.810	1.032	1.277	1.613	1.918	2.309	-	-
150	-	-	-	-	-	-	-	0.846	1.077	1.332	1.678	1.994	2.400	2.776	-
160	-	-	-	-	-	-	-	0.881	1.122	1.388	1.744	2.070	2.491	2.878	3.504
170	-	-	-	-	-	-	-	-	1.167	1.443	1.809	2.147	2.582	2.979	3.624
180	-	-	-	-	-	-	-	-	1.212	1.499	1.874	2.223	2.673	3.080	3.745
190	-	-	-	-	-	-	-	-	-	1.554	1.939	2.300	2.763	3.181	3.865
200	-	-	-	-	-	-	-	-	-	1.610	2.004	2.376	2.854	3.282	3.986
210	-	-	-	-	-	-	-	-	-	-	2.069	2.452	2.945	3.383	4.106
220	-	-	-	-	-	-	-	-	-	-	2.134	2.529	3.036	3.484	4.347
230	-	-	-	-	-	-	-	-	-	-	-	2.605	3.127	3.535	4.347
240	-	-	-	-	-	-	-	-	-	-	-	-	3.218	3.687	4.468
250	-	-	-	-	-	-	-	-	-	-	-	-	-	3.788	4.588
260	-	-	-	-	-	-	-	-	-	-	-	-	-	-	4.709

1.2, 1.3. (Revised edition, Amendment No. 2).

2. Technical requirements

2.1. Studs shall be manufactured in accordance with the requirements of this standard, to working drawings approved in the prescribed manner.

2.2. Studs shall be manufactured from bar stock or forgings.

2.3. Steel grades and their application parameters shall comply with those specified in Table 4.

Table 4

Steel grade	Standard designation	Limiting application parameters
		temperature, °C	nominal pressure, MPa (kgf/cm²)
35Kh	GOST 4543	From minus 50 to plus 200	≈63(630)
38KhA
40Kh
35KhM		From minus 50 to plus 400	≈80(800)
30KhMA
40KhFA
25Kh1MF	GOST 20072	From minus 50 to plus 510	≈100(1000)
25×2M1F

Note. Subject to agreement between the customer and the manufacturer, other steel grades approved by Gosgortekhnadzor of the USSR may be used, provided their mechanical properties are not lower than those specified in Table 5.

2.4. Blanks for stud manufacture shall be subjected to heat treatment — quenching and tempering. Heat treatment modes are given in the appendix.

2.5. The mechanical properties of blanks at a temperature of 20 °C in the heat-treated condition shall comply with those specified in Table 5.

Table 5

Steel grade	Yield strength σ0.2, MPa (kgf/mm²)	Tensile strength σB, MPa (kgf/mm²)	Elongation δ₅, %	Impact strength αn, J/cm² (kgf×m/cm²)	Hardness HB
		min
35Kh; 38KhA; 40Kh	³588 (60)	735 (75)	14	58.8 (6)	235-277
35KhM; 30KhMA; 40KhFA	637-784 (65-80)	785 (80)	13		248-293
25Kh1MF	667-784 (68-80)		16
25×2M1F			12	49.0 (5)

(Amended edition, Amendment No. 1).

2.6. The acceptance characteristics are tensile strength, yield strength, elongation and impact strength.

2.7. The thread is a coarse-pitch metric thread per GOST 24705 with tolerance class 6g per GOST 16093.

2.8. The thread runout is normal per GOST 10549; the thread root form is rounded per GOST 9150.

2.7, 2.8. (Revised edition, Amendment No. 1).

2.9. When the thread is formed by rolling, it is permitted to manufacture the thread with a 30° end chamfer.

2.10. When the thread is formed by cutting, the diameter of the plain section of the studs is, for types:

A — per GOST 19258;

B — in accordance with Table 1.

When the thread is formed by rolling, the diameter of the plain section of the studs shall be per GOST 19256.

2.11. The thread shall be clean and shall have no burrs or torn threads. Dents on the thread that prevent the go gauge from being screwed on are not permitted.

The threaded and plain surfaces of the studs shall have no cracks.

2.12. The permissible offset of the thread axis relative to the axis of the plain section of the stud shank shall be per h12 GOST 25347.

2.13. Unspecified limit deviations of shaft dimensions shall be per h14, and of other dimensions — per ±GOST 25347.

2.12, 2.13. (Revised edition, Amendment No. 1).

2.14. The stud shank shall be straight. The permissible curvature of the stud shank per 100 mm of length shall not exceed:

0.2 mm — for stud diameters from 12 to 24 mm;

0.1 — for stud diameters above 24 mm.

2.15. Studs may be manufactured with center holes per GOST 14034.

2.16. Studs used at temperatures up to 200 °C are manufactured with a coating at the customer’s request. The coating type shall be per GOST 9.303. The coating thickness shall be per GOST 9.306. The coating designation shall be per GOST 1759.0.

(Revised edition, Amendments No. 1, 2).

2.17. Protective coatings shall be uniform. Blisters and peeling are not permitted.

2.18. Requirements for the surface roughness under the coating shall be per GOST 9.301.

3. ACCEPTANCE RULES

3.1. Acceptance rules — per GOST 17769.

3.2. Each stud shall be inspected for compliance with the requirements of Clauses 1.1, 2.7-2.18, 5.1, 5.2.

3.3. Studs shall be submitted for acceptance in lots. A lot consists of studs of one designation, manufactured from one lot of blanks.

3.4. Studs shall be checked for compliance with the requirements of Clause 2.5 on the basis of the test results for each lot of blanks.

3.5. A lot of blanks consists of metal from one melt and one heat-treatment batch.

3.6. Blanks shall be tested for hardness at 100% rate. For blanks longer than 500 mm, hardness shall be measured at both ends and along the length at intervals not exceeding 500 mm.

3.7. One percent of the blanks from the lot, but not fewer than two pieces, with the lowest and highest hardness values in that lot, shall be tested for compliance with the requirements of Clause 2.5.

Blanks with intermediate hardness values may be selected for mechanical testing. In this case, hardness shall be an acceptance characteristic.

3.8. The number of specimens tested from each inspected blank: 1 for tensile testing and 2 for impact testing.

3.9. Impact testing of blanks for M12 and M14 studs may be omitted.

3.10. If unsatisfactory mechanical property test results are obtained for at least one specimen, repeat tests shall be carried out on double the number of specimens from the same blanks or other blanks of the same lot with the same hardness, only for the type of test that gave the unsatisfactory result.

3.11. A batch is considered acceptable if repeated tests give positive results. If unsatisfactory test results are obtained, the batch of blanks may be resubmitted for acceptance after testing blanks with the next hardness level.

3.12. Blanks with a hardness that does not provide the required mechanical properties specified in Table 5 may be accepted for delivery after repeated heat treatment, with the corresponding tests performed.

The number of repeated heat treatments shall not exceed two. Additional tempering is not considered a repeated heat treatment.

4. TEST METHODS

4.1. Visual inspection (clauses 2.11, 5.1, 5.2) is performed without the use of magnifying instruments.

4.2. Stud dimensions (clauses 1.1, 2.7–2.10, 2.12–2.15) are checked with limit gauges, templates, and universal measuring instruments.

4.3. Hardness determination (clause 2.5) - according to GOST 9012.

4.4. Tensile testing (clause 2.5) - according to GOST 1497.

4.5. Impact toughness testing (clause 2.5) - according to GOST 9454-78, specimen type 1.

4.6. Sampling method (clause 2.5) - according to GOST 7564.

4.7. Methods for checking coating quality and thickness (clauses 2.16–2.18) - according to GOST 9.302. Coating thickness is checked on the stud shank.

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

5.1. Marking of studs, depending on steel grade, corresponds to that specified in Table 6.

Table 6

Steel grade	Marking
35Kh; 38KhA; 40Kh
35KhM; 30KhMA; 40KhFA
25Kh1MF; 25Kh2M1F

Notes:

1. Marking on the end face of the shank is permitted.

2. The marking shall be retained when the steel is replaced with an equivalent grade.

5.2. Marking indicating the following is applied to studs at the locations specified in Table 6:

lot number;

trademark of the manufacturer.

5.3. Height of marking characters:

2.5 mm - for studs with d ≤ 27 mm;

4 mm - for studs with d > 27 mm.

5.4. Marking symbols shall be clearly visible to the naked eye.

5.5. Marking is performed by the stamping (impact) method.

5.6. A batch of studs shall be accompanied by a quality passport certifying that the studs comply with the requirements of this standard.

The quality passport contains the following data:

name of the manufacturer;

designation of the studs;

number of studs;

lot number;

steel grade;

number of this standard;

test results (with the date indicated);

type and thickness of coating (for coated studs);

stamp of the quality control department.

5.7. (Deleted, Amendment No. 1).

5.8. Requirements for packaging, transportation, storage, and marking of containers - according to GOST 18160.

5.9. When stored indoors, studs shall be kept in containers.

5.10. By agreement between the customer and the manufacturer, coated studs are permitted not to undergo preservation treatment.

Appendix

Recommended

Heat treatment conditions for blanks

Steel grade	Quenching		Tempering
	heating temperature, °C	cooling medium	heating temperature, °C	cooling medium
35Kh	850-870	Oil	500-540	Water and oil
38KhA	850-870		530-580
40Kh	850-870		530-580
30KhMA	850-890		530-570
35KhM	850-870		560-600
40KhFA	870-890		630-660
25Kh1MF	930-950		620-660
25×2M1F	Double normalizing at 1030-1050 and 950-970		680-700

Designation of the referenced regulatory document	Clause number	Designation of the referenced regulatory document	Clause number
GOST 9.301-86	2.18	GOST 10549-80	2.8
GOST 9.302-88	4.7	GOST 14034-74	2.15
GOST 9.303-84	2.16	GOST 16093-81	2.7
GOST 9.306-85	2.16	GOST 17769-83	3.1
GOST 1497-84	4.4	GOST 18160-72	5.8
GOST 1759.0-87	2.16	GOST 19256-73	2.10
GOST 4543-71	2.3	GOST 19258-73	2.10
GOST 7564-97	4.6	GOST 20072-74	2.3
GOST 9012-59	4.3	GOST 24705-81	2.7
GOST 9150-81	2.8	GOST 25347-82	2.12, 2.13
GOST 9454-78	4.5