This standard specifies the polarization, grades, technical requirements, test methods and inspection rules of chromite sand for casting. This standard applies to chromite sand used for mold core making in foundry production. JB/T 6984-1993 Chromite sand for foundry JB/T6984-1993 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Chromite Sand for Casting
Subject Content and Scope of Application
JB/T6984
This standard specifies the chromite sand for casting The classification, brand, technical requirements, test methods and inspection rules, etc. This standard is applicable to chromite sand used for molding and core making in foundry production. 2 Reference standards
GB2684
Test method for source sand and skin mixture for casting
GB9442 Silica sand for casting
ZBJ31004 Test sieve for casting
YB368 Refractory degree Inspection method
YB778 refractory chemical analysis method
Natural spinel, mainly iron ore, is crushed into sand with a certain particle size, suitable for modeling (core making). 3.2 Moisture content
is the percentage of the weight lost by the sample after drying at 105~~110C to the weight of the original sample. 3.3 Loss on ignition
93
The loss on ignition refers to the sample after drying at 105~110℃ to remove free moisture, and then burning it to the bait weight at a high temperature of 950~1000C. Loss on ignition as a percentage of the weight of the dried sample. 4. Classification, grouping and grade
4.1 Classification
Chromite sand for casting is divided into two levels according to the physical and chemical properties (mainly Cr2O, content), see Table 1. Table 1
Level number
Level
Level
4.2 group
Ctra0)
45
W35||tt ||Sio
5
Chromite sand for foundry is divided into three grades according to different particle sizes, see Table 2. The Ministry of Machinery Industry of the People's Republic of China approved Cao
loss on ignition
o.5
moisture content
0.5
0.5| | tt | ||21
15
10
No.
JB/T6984---93
Table 2
Main particle size composition, mm
0.300,
0.212.0.150
0.150.0.106
0.212.
0.150.
0.106.
0.075
Note: The main particle size composition means that the sum of the residues in the three adjacent sieve holes is not less than 75%, the residue in the middle sieve is not less than 25%, and the residue in the chassis is less than 2? 4.3 gradewwW.bzxz.Net
The expression method of chromite sand grades for casting is as follows: ZGTS
Example.zGrs1-21
5 Technical requirements
XX
Particle size grouping code
Three Chromium oxide (C)) classification code
Chromite sand towel for casting "cast, chromium, iron, sand" Chinese Pinyin prefix 5.1 The appearance should be bright black or dark brown, and the particle size should be uniform. 5.2 Chemical composition
The chemical composition of chromite sand for casting is mainly based on the percentage content of chromium monoxide, silicon monoxide, and calcium oxide, which should be in compliance with the meeting table! Regulations:
5.3 The refractoriness, ignition loss and moisture content of cast Sichuan chromite sand should comply with the requirements in Table 1. 5.4 Particle size composition
The particle size composition of chrome shovel sand for casting shall comply with the requirements in Table 2. 5.5 If there are requirements for the technical items listed in this standard, the supply and demand parties shall stipulate them in the agreement. 6 Test Methods
6.1 Appearance: Measure.
6.2 The determination of chromium trioxide (Cr.0), silicon dioxide (SiO)) and calcium oxide (CaO) is carried out according to YB879. 6.3 The measurement of loss on ignition shall be carried out according to YB3778. 6.4 The measurement of refractoriness shall be carried out according to YB368. 6.5 Particle size grouping and moisture content determination shall be carried out in accordance with GB2684. 6.6 The test sieve is selected according to the regulations of ZBJ31004. 7
Inspection rules
7.1 The testing and sampling methods of chromite ore for foundry shall be carried out in accordance with GB2684. 7.2 Each batch of chromite ore supplied by the supplier must be in accordance with the standard and agreed upon by both parties. The items should be inspected, and the inspection results and brand names should be written in the quality certificate, and the purchaser will conduct acceptance accordingly. 7.3 The purchaser can conduct necessary random inspections based on the quality certificate. If there is any discrepancy, it can be re-inspected with the supplier. 8 Marking, packaging, transportation and pasting
8.1 Packaging is divided into two types: 25kg and 50kg net weight per bag. 8.2 The packaging bag manufacturer should have a clear sign indicating the supplier's factory name, product name, brand, weight, batch number, etc. JB/T6984-93
The packaging must be tight, clean and moisture-proof, and can be packed in woven bags lined with plastic bags. 8.3
8.4 Different grades of chromite sand must be shipped and stored separately. Transportation and Keep away from rain and blisters during storage. Additional notes:
This standard is proposed by the Ministry of Machinery Industry.
This standard is recommended by the Shenyang Casting Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shenyang Casting Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Fu Zhiwei and Liu Shoubin. 2
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