GOST 21990-76

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  ГОСТ 21990-76

GOST 21990−76 plates of magnesium alloys. Specifications (with Amendments No. 1, 2, adjusted)

GOST 21990−76*

Group В53

STATE STANDARD OF THE USSR

PLATES OF MAGNESIUM ALLOYS

Specifications

Magnesium and magnesium alloys plates.
Specifications

Date of introduction 1978−01−01

The decision of the State Committee of standards of Ministerial Council of the USSR from June 29, 1976 N 1620 introduction installed with 01.01.78

Resolution of the state standard from 07.09.92 N 1121 removed the limitation of the validity period

* REPRINT (February 1997) with Amendments No. 1, 2 approved in June 1987, September 1992 (IUS 11−87, 12−92)

Amended, published in the IUS N 8, 1997

An amendment made by the manufacturer of the database

This standard applies to hot-rolled plates of magnesium alloys.

(Changed edition, Rev. N 1).

1. ASSORTMENT

1.1. The thickness of the plates, limit deviations on thickness depending on thickness and width shall be as specified in table.1.

Table 1

mm

The thickness of the plate	Maximum deviation in thickness when the width of the plate
500	600	700	800	900	1000
12 14 16 18 20	±0,5	±0,5	±0,5	±0,5	±0,5	±0,5
22 25	±0,75	±0,75	±0,75	±0,75	±0,75	±0,75
27 30 32 35	±1,0	±1,0	±1,0	±1,0	±1,0	±1,0
40 45	±1,5	±1,5	±1,5	±1,5	±1,5	±1,5
50	-	-	-	±2,0	±2,0	±2,0

1.2. The length of the plates depending on their thickness and width shall be as defined in table.2.

Table 2

mm

The thickness of the plate	Length of plate with a width
500; 600;	700;	800; 900	1000
From 12 to 20	2000;	2500;	3000	2000;	2500;	3000
SV. 20 «25	2000;	2500;	3000	2000;	2500;
«25» 32	2000;	2500;	2000;
«32» 35	1000;	1500;	2000	1800;
«35» 40	1000;	1500;	1800	1000;	1600;
«40» 50	1000;	1300;	1000;	1200;

1.3. At the request of the customer can be manufactured slabs with intermediate sizes.

The maximum deviations in thickness are taken as the nearest smaller size.

1.4. Limit deviations on width of sheared plates up to a thickness of 32 mm shall not exceed ±15 mm.

1.5. Maximum deviations along the length of the cropping slabs with a thickness up to 32 mm shall not exceed ±30 mm.

1.6. Theoretical mass () of one meter length of the plate, kg, is calculated by the formula

,

where ,  — the maximum size limits on thickness and width, mm;

that is the smallest size limits on thickness and width, mm;

 — the density of magnesium alloy, g/cm.

Theoretical weight plates of one meter length are given in Appendix and calculated at a density of 1.79 g/cm, which corresponds to the density of magnesium alloys MA2−1 and MA2−1 p. h.

Example the legend plate of alloy grade MA2−1 p. h, thickness 20 mm, width 1000 mm, length 2500 mm

Plate MA2−1 p. h. 20х1000х2500 GOST 21990−76

(Changed edition, Rev. N 1, 2).

2. TECHNICAL REQUIREMENTS

2.1. Plates are made in accordance with the requirements of this standard in accordance with technical documentation approved in the established procedure, the magnesium alloys MA2−1, MA2−1 p. h. with the chemical composition according to GOST 14957−76.

(Changed edition, Rev. N 1).

2.2. Plates are produced without heat treatment.

2.3. The mechanical properties of the plates must meet the requirements specified in table.3.

(Amendment. ICS N 8−97).

Table 3

Grade	Plate thickness, mm	Tensile strength, kgf/mm	The yield stress , kgf/mm		Elongation ,%, at
tensile	compression
not less than
MA2−1	From 12 to 20	25,0	14,0	8,0	7,0
SV. 20 «32	25,0	14,0	8,0	6,0
«32» 50	23,0	-	-	6,0
MA2−1 p. h.	From 12 to 20	25,0	14,0	8,0	8,0
SV. 20 «32	25,0	14,0	8,0	8,0
«32» 50	23,0	-	-	6,0

(Changed edition, Rev. N 1, 2).

2.4. Plate thickness up to 32 mm is made with trimmed edges and ends, without burrs. Plate thickness more than 32 mm are made with mill ends and edges.

2.5. The surface of the plates should be subjected to anti-corrosion treatment according to normative-technical documentation approved in the established order.

2.6. The plate surface should be free of captivity, cracks, flaws, delamination and flux slag inclusions and iron oxides.

On the surface of the plates allowed the tears, scuffing, scratches, dents and bulges, risks, Rabina and single metallic and non-metallic inclusions in the form of points, if the depth defined by the reference sweep, does not exceed the lower limit deviation on thickness.

On uncut edges and ends of the plates allowed defects due to the method of production, do not interfere with the cutting of a rectangular plate of nominal sizes.

2.5, 2.6. (Changed edition, Rev. N 2).

2.7. After machining the consumer on the surface of the plates allowed individual and group clusters of manganese.

The value of the total area of the clusters of manganese per 1 mof the surface plates should be not more than 300 mm — grade alloy MA2−1 and 200 mm — grade alloy MA2−1 p. h.

The area of one of the clusters for grade alloy MA2−1 must not exceed 100 mm, and the size of each of the other clusters — 50 mm; the area of each cluster for grade alloy MA2−1 p. h. should not exceed 30 mm.

Flux and slag inclusions are not allowed.

2.8. General waviness in the transverse and longitudinal directions of the plates should not exceed 15 mm.

3. ACCEPTANCE RULES

3.1. Plate presented to the receiving parties. The party should consist of slabs of the same brand of alloy, of the same size, and be accompanied by a document about quality that contains:

trademark or a trademark and the name of the manufacturer;

the symbol plates;

test results (mechanical properties indicate only the maximum and minimum values);

batch number;

the weight of the party;

the date of shipment;

the designation of this standard.

The weight of the batch is not limited.

The filler can be a party of a few of swimming trunks, provided that each melting meets the requirements of this standard.

(Changed edition, Rev. N 1).

3.2. The ingots of each heat before starting the treatment subjected to chemical analysis to determine the content of alloying elements and impurities.

3.3. The dimensional control subjected to each plate.

3.4. Check the status of the surface subjected to each plate.

(Changed edition, Rev. N 2).

3.5. Checking the waviness is subjected to each plate thickness of 32 mm.

(Changed edition, Rev. N 1).

3.6. Verification of mechanical properties in tension and compression is a destructive method, or by eddy currents subjected to 10% plates thickness up to 32 mm, but not less than one plate from the party.

3.7. Verification of the yield strength in compression is subjected to plate thickness from 20 to 32 mm.

3.8. If from the same ingot are rolled two or three plates, the test of mechanical properties carried out on the workpiece, select between the two fold plates. Thus all the multiple plates brand the same room.

(Changed edition, Rev. N 2).

3.9. If unsatisfactory test results a destructive method at least one indicator thereon, a second check for twice the number of samples taken from the same plates.

If unsatisfactory results of repeated tests of the plate are subjected to continuous testing.

3.10. If unsatisfactory test results of the eddy current plate is subjected to continuous control.

4. TEST METHODS

4.1. Inspection surface plates are produced without the use of magnifying devices.

4.2. Check the size of the plates is performed using the measuring instrument to ensure the required measurement accuracy.

The thickness of the plates measured by Vernier caliper according to GOST 166−89.

Measurement of the width and length of the plates is carried out metal measuring tape measure the churchyard 7502−89*.
_______________
* On the territory of the Russian Federation GOST 7502−98. — Note the manufacturer’s database.

(Changed edition, Rev. N 1).

4.3. Testing of mechanical properties carried out on samples that have not undergone heat treatment.

4.4. Testing of mechanical properties carried out by destructive testing in accordance with GOST 1497−84 or by nondestructive testing using eddy currents according to the reference document, duly approved.

4.5. Determination of the yield stress under compression is produced by NTD, duly approved.

4.6. Samples for testing mechanical properties destructive method selected from the middle layers of the plate in the longitudinal direction.

4.7. To check the mechanical properties of each slab sample cut two samples: one to determine the mechanical properties tensile, and the second to determine the yield strength in compression.

4.8. In case of impossibility of producing a standard sample testing carried out on the samples, the shape and dimensions of which are set by the manufacturer.

4.9. Inspection non-destructive method of eddy currents produced on the surface of the plates or blanks cut from plates.

4.10. The measurement of the thickness of the plates is done at a minimum distance of 115 mm from the vertex of the angle and not less than 25 mm from the edge of the plate.

4.11. Waviness is determined by the greatest distance between the flat surface and the lower surface of the plate or between the upper surface of the plate and the adjacent plane parallel to the flat surface.

The measurement is performed using one of the methods specified in GOST 26877−91, using a metal ruler according to GOST 8026−92 and GOST 427−75.

(Changed edition, Rev. N 1).

4.12. Determination of the chemical composition produced according to GOST 3240.0−76 — GOST 3240.21−76 host 7728−79.

5. MARKING, PACKAGING, TRANSPORTATION AND STORAGE

5.1. On each plate on one of the corners at a distance of not more than 25 mm from edge width of the plate should be marked with indication of alloy grades, batch number, serial number plate and stamp of the technical control Department.

5.2. Preservation, packing, marking and transportation is made according to GOST 9.511−93.

By agreement between the consumer and the manufacturer plate can be supplied without preservatives.

5.3. (Deleted, Rev. N 1).

5.4. Plates should be stored in covered warehouses excluding ingress of moisture, the active chemicals, and mechanical damage.

APP (mandatory)

APP
Mandatory

Plate thickness, mm	The theoretical mass of the plate of 1 m length, kg
Plate width, mm
500	600	700	800	900	1000
12	10,740	12,888	15,036	17,184	19,332	21,480
14	12,530	15,036	17,542	20,048	22,554	25,060
16	14,320	17,184	20,048	22,912	25,776	28,640
18	16,110	19,332	22,554	25,776	28,998	32,220
20	17,900	21,480	25,060	28,640	32,220	35,800
22	19,690	23,628	27,566	31,504	35,442	39,380
25	22,375	26,850	31,325	35,800	40,275	44,750
27	24,165	28,998	33,831	38,664	43,497	48,330
30	26,850	32,220	37,590	42,960	48,330	53,700
32	28,640	34,368	40,096	45,824	51,552	57,280
35	31,325	37,590	43,855	50,120	56,385	62,650
40	35,800	42,960	50,120	57,280	64,440	71,600
45	40,275	48,330	56,385	64,440	72,495	80,550
50	-	-	-	71,600	80,550	89,550

(Changed edition, Rev. N 1).

The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: IPK Publishing house of standards, 1997