This standard specifies the definition, names of various parts, technical requirements, test methods, inspection rules, packaging, marking and transportation of red artificial corundum. This standard applies to red artificial corundum pear crystal grown by flame fusion method for manufacturing gemstones such as watches, instruments and handicrafts. GB/T 4051-1997 Red artificial corundum GB/T4051-1997 standard download decompression password: www.bzxz.net

GB/T 4051—1997
This standard is revised from the original GB4051-83 (Red artificial corundum for watches and clocks). During the revision process, the relevant technical contents of the original GB4051-83 were adjusted and revised, and its articles were rearranged. This standard has some changes in the following chapters and contents: - The writing format and expression method are implemented in accordance with the requirements of GB/T1.1-1993 Standardization Work Guide Unit 1: Drafting and Expression Rules of Standards Part 1: Basic Regulations for Standard Writing, and
Chapter 2 Definitions is added!
-4.1, 4.2, 4.3 have adjusted the size range of the outer dimensions and equal diameter parts of the semi-boulder crystal, and 4.1 and 4.4 have divided the original I, 1, and 1 grades into A, B, and C grade III, and added the requirements for the height of the split surface other than equal diameter,
- Chapter 6 adds the specific operation content of the test method; - 7.2, 7.3 make specific provisions and supplements for packaging and marking. This standard replaces GB4051-83 from the date of entry into force. The appendix to this standard is a prompt appendix.
This standard is proposed by the Quality Standards Department of the China Light Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Watches and Clocks. The drafting unit of this standard: Nanjing Watch and Clock Material Factory. The main drafters of this standard: Shen Yufen, Cao Xinghua, Liu Guodao. This standard was first issued on October 17, 1983 and revised for the first time in 1997. 139
1 Scope
National Standard of the People's Republic of China
Red artificial corundumwww.bzxz.net
Cal synthetic ruby
GB/T 4051--1997
Replaces GB1051-83
This standard specifies the definition, names of various parts, and technical requirements of red artificial corundum. Test methods, inspection rules, and packaging, marking, and transportation.
This standard applies to red artificial corundum pear crystals grown by flame fusion for the manufacture of gem components such as watches, instruments, and handicraft accessories. 2 Definitions
This standard adopts the following definitions.
2.1 Red artificial corundum
A red pear-shaped single crystal formed by melting -Al.O. powder doped with Cr2O3 at high temperature in a sintering furnace and crystallizing it on a pre-oriented seed crystal.
2.2 Semi-pear crystal
Artificial corundum pear A crystal that is split into two halves along the crystal planes oriented along the optical axis and the growth axis. 2.3 Cleavage plane (split plane)
The property of a crystal that can often split along one or some crystal planes with a certain orientation is called the cleavage property of the crystal. Such a crystal plane is called a cleavage plane or split plane. A smooth surface is a fine surface, and a wavy surface is a rough surface. 2.4 Orientation angle
The angle between the optical axis and the growth axis.
2.5 Polished surface
The surface of the pear crystal cylinder is glassy and evenly or sparsely covered with a velvety thin layer without powder. 2.6 Melt nodule
The entire circle or partial overmelting produced on the surface of the pear crystal during its growth process is called overflow if it is in a single phase, and melt nodule if it is in a two-phase (with an unmelted powder pile).
2.7 Unmelted matter
Incompletely melted powder or impurities inside the pear crystal. Unmelted materials are in the form of layers and dots (or masses). 2.8 Bubbles
Pores and cavities inside the pear crystal.
3 Names of various parts
The names of various parts of red artificial corundum semi-pear crystal (hereinafter referred to as semi-pear crystal) are shown in Figure 1. Approved by the State Administration of Technical Supervision on May 28, 1997 140
Implementation on January 1, 1998
GB/T 4051-1997
Round head item
Growth axis
Directional pain
Expanded part
Inoculation site
D is the diameter of the round head, L is the length of a semi-crystal, d is the diameter of the expanded part of the semi-pear crystal (the length measured from the inoculation site is equal to the diameter at 13mm) Figure 1
4 Technical requirements
The quality grade of the outer dimensions of the semi-pear crystal shall be as specified in Table 1. Table 1
Diameter of round head D
Length of half boli
Diameter of enlarged part d
Conical part of equal diameter
22≥D≥18
62≥L≥44
Conical part of equal diameter drum, saddle, curved
4.2All parts of A-grade semi-boli should be complete. 1One place
Quality grade
24≥D≥16
64≥L≥40
《Two places
2—place
2Two places
3—place
4.3When the bottom of the cone of B-grade semi-boli is incomplete, the upper limit of the length is reduced to 56mm. 4.4The equal diameter part refers to the cylindrical part from more than 20mm from the inoculation point to less than 5mm from the top of the round head. Drum, saddle and bend with diameter difference less than 0.3mm do not affect the quality grade. 4.5 The quality requirements of each grade of semi-pear crystal shall comply with the provisions of Table 2. 141
Smooth surface height, mm
Melted mass,
Unmelted matter,
Bubble,
Crack, strip
Orientation angle, (\)
Equal diameter part face height, mm
Other part face height. mm
GB/T 4051—1997
Quality grade
Not allowed
Not allowed
Not allowed
Not allowed
Comprehensive
Utilization rate except the three defects is 70%
4.6 The appearance of semi-pear crystal is red, and the surface is evenly covered with powdery material like velvet. The rounded head part is convex or flat, and the semi-boulder with concave top is unqualified.
4.7 Except for cracks, other defects within 5mm below the top of the semi-boulder are not counted, and various defects within 8mm from the cone bottom to the inoculation point are not counted. The height of the facets of these two parts can be specified in Table 2. 4.8 The unmelted material of the B-grade semi-boulder shall not cross the semi-boulder, and the crack shall not be deeper than one-fourth of the diameter and the length shall not exceed 5mm. 4.9 The split surface of the semi-boulder is fine or rough, which does not affect the quality grade. The semi-boulder that is automatically split without splitting can only be regarded as C-grade products if it meets the standards.
4.10 The overmelting of the semi-boulder is overflow and does not affect the quality grade; the molten nodules on the same horizontal circumference are counted as one place. The width of the B-grade molten nodules should be less than or equal to 3mm, and those greater than 3mm will be downgraded. 4.11 The brittleness requirements of the semi-boulder can be agreed upon by the supply and demand parties when necessary. 5 Test method
5.1 The quality test of half-boil crystal shall be carried out in accordance with the provisions of Table 3. Table 3
Test items
Diameter of round head
Diameter of enlarged part
Length of half boule
Cone of equal diameter part
Test conditions and apparatus
Under 100W incandescent light
Vernier caliper (scale value 0.5mm)
Vernier caliper, special sample
Vernier caliper
Vernier caliper
Test method
Visual inspection with normal vision
Measure within 6~10mm below the top of the round head
Insert the enlarged part into the sample and measure the length of the inoculation
Measure the length of the inoculation from the top of the round head to the bottom of the cone
Measure 20mm from the inoculation and the top of the round head
6~10 below the item mm Difference between the largest and smallest diameters at two locations
Corresponding clauses
4.1, 4.2.4.3
Test items
Drum, saddle, bend of equal diameter parts
Surface height
Bubble, unmelted matter, nodule, crack
Section surface height
Orientation angle
GB/T 4051-1997
Table 3 (end)
Test conditions and instruments
Vernier caliper
Vernier caliper
Under 100W incandescent light in dark field
Splash test method
Measure the difference between the maximum and minimum diameters of two adjacent expansion and contraction points
Measure the head from the top of the round head, and measure other parts according to the actual measurement
Normal force visual inspection
Vernier caliper, feeler gauge, special flat glass [Put the half pear crystal flat on the glass to measure the height of the curved glass
Polarizing microscope
The height of the warp
According to the instruction manual
5.2 The section inspection method for the brittleness of red artificial corundum is shown in Appendix A (suggestive appendix). 6 Inspection rules
Corresponding clauses
4.5.4.7.4.8.4. 10
4.5, 4.9
6.1 The quality inspection department of the manufacturer shall inspect each half-bottle crystal one by one and ensure that the product quality meets the requirements of this standard6.2 Users can conduct re-inspection or random inspection of each batch of semi-bore crystals according to the provisions of this standard. The inspection quantity is 10% of the batch. The number of semi-bore crystals sampled in each batch shall not be less than 50, and the grade error rate shall not exceed 5%. If it exceeds the regulations, double the number must be sampled for re-inspection. If it still exceeds the regulations, the batch of artificial corundum semi-bore crystals will be returned for re-inspection. 7 Packaging, marking, and transportation
7.1 Semi-bore crystals shipped from the factory should be packaged separately according to grade. Put them in paper boxes in layers, and fill the gaps around them with soft materials to prevent the semi-bore crystals from sliding, colliding, and breaking.
7.2 Each packaging box should be accompanied by a product certificate, which should indicate: a) the name and address of the manufacturer;
b) the product name and registered trademark,
c) the product grade and weight;
d) the inspection date and inspector code,
e) the number of this standard.
7.3 The following signs should be on the packaging box:
a) manufacturer name and trademark,
b) product name;
c) product grade and weight;
d) "Handle with care" sign.
7.4 Avoid violent vibration during transportation and handle with care during loading and unloading. 143
A1 Sampling
GB/T 4051--1997
Appendix A
(Suggestive Appendix)
Red artificial corundum brittle slice inspection method Every 10-50kg half-boil crystal is a batch, and 1kg is randomly selected as a sample. A2 Orientation
Same as the processing procedure of gemstone components.
A3 Gluing
Same as the processing procedure of gemstone components.
A4 Machine tool
Same as gemstone component processing and cutting machine, but relatively fixed. There should be no problems caused by unstable pressure or other mechanical movement failures during the cutting process.
A5 Slicing
New blades must be used for slicing assessment. Pay attention to the quality of the blades used and the consistency of the number of cuts per pair of blades. A6 Slicing specifications
Slicing specifications are agreed upon by both the supplier and the buyer.
A7 Slicing operation
A7.1 The feed pressure should be kept constant and the cutting oil should be fully cooled. A7.2 The slicing time for each plate should be kept relatively constant. A7.3 Slicing should be done by a dedicated person.
A8 Inspection
A8.1 The broken pieces should be checked and weighed (corundum pieces that fall off during slicing will not be assessed). All corundum pieces with cracks are counted as fragments (or according to the sealed sample).
A8.2 Inspection should be done by a dedicated person and original records should be kept. A9 calculation method
Broken moss slice weight
Slice broken phosphorus rate (%) = No grid slice quantity Slice capsule phosphorus slice weight × 100144
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