Handan city Yongnian District Maide Fasteners Co. Ltd
Handan city Yongnian District Maide Fasteners Co. Ltd Galvanized Hex Bolts，Fully Threaded Hex Bolts，Galvanized Hex Nut
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Hot Dip Galvanized Flat Metal Washers , Precision Flat Ring Gasket 4.8 8.8 Grade
Product Description
According to the standard, flat washers of 100HV and 140HV can be made of mild steel. Most of the general enterprises use Baosteel materials when selecting materials, which facilitates cold stamping. The Q/BQB403-2003 Baosteel standard is briefly described below.
There are major changes in the "Cold Rolled Low Carbon Steel Plate and Strip" and Q/BQB403-2003 corporate standards compared to the BZJ407-1999 standard:
(1) The brand number was modified and integrated. There are 8 commonly used brands and 5 integrated products. St12 changed to DC01; ST13 to DC03; St14, St15 to DC04; BSC2 to DC05; St16, St14-T, BSC3 to DC06.
(2) The surface quality level was modified from two to three:
Higher grade finishing surface (FB), the surface allows a small number of defects that do not affect the formability and coating, plating adhesion, such as minor scratches, indentation, pitting, roller printing and oxidation color.
The better of the two sides of an advanced finished surface (FC) product has no visible defects on the naked eye and the other side must meet at least the FB requirements.
The better side of the super-finished surface (FD) product must have no imperfections, ie it must not affect the appearance quality after painting or the appearance quality after electroplating. On the other hand, it must meet at least the requirements of FB.
(3) The surface structure was modified from four to two, and the control value of the surface roughness was increased. The average roughness Ra when the surface structure was a matte surface (D) was 0.6 μm.
(4) The specification of Si and residual elements in the chemical composition of the five grades was eliminated, and the contents of elements such as C, S, and Alt were modified.
The Role of Flat Mat
1. Increase the contact area between the screw and the machine.
2. Eliminate damage to the surface of the machine when the spring pad is unloaded. When used, it must be a spring pad and a flat pad. The flat pad is facing the surface of the machine. The spring pad is between the flat pad and the nut.
Flat pad standard
National standards are different.
Here is the United States flat pad standard:
| Specification | Minor Diameter | Outside Diameter | Thickness Tolerance | Thickness Tolerance Disintegration |
| USS 3/16 | 6.22～6.73 | 14.15～14.66 | 0.91～1.65 | 0.91～1.40 |
| 1.40～1.65 | ||||
| USS 1/4 | 7.80～8.31 | 18.47～19.02 | 1.30～2.03 | 1.30～1.65 |
| 1.65～2.03 | ||||
| USS 5/16 | 9.40～9.91 | 22.05～22.99 | 1.63～2.64 | 1.63～2.20 |
| 2.20～2.64 | ||||
| USS 3/8 | 11.00～11.51 | 25.22～26.16 | 1.63～2.64 | 1.63～2.20 |
| 2.20～2.64 | ||||
| USS 7/16 | 12.57～13.08 | 31.57～32.51 | 1.63～2.64 | 1.63～2.20 |
| 2.20～2.64 | ||||
| USS 1/2 | 14.15～14.60 | 34.75～35.69 | 2.18～3.35 | 2.18～2.70 |
| 2.70～3.00 | ||||
| 3.00～3.35 | ||||
| USS 9/16 | 15.75～16.26 | 37.13～38.07 | 2.18～3.35 | 2.18～2.70 |
| 2.70～3.00 | ||||
| 3.00～3.35 | ||||
| USS 5/8 | 17.30～18.24 | 44.27～45.21 | 2.74～4.06 | 2.74～3.20 |
| 3.20～3.60 | ||||
| 3.60～4.06 | ||||
| USS 3/4 | 20.45～21.39 | 50.62～51.56 | 3.10～4.50 | 3.10～3.60 |
| 3.60～4.20 | ||||
| 4.20～4.50 | ||||
| USS 7/8 | 23.65～24.58 | 56.97～57.91 | 3.45～4.88 | 3.45～4.00 |
| 4.00～4.30 | ||||
| 4.30～4.88 | ||||
| USS 1 | 26.80～27.74 | 63.32～64.26 | 3.45～4.88 | 3.45～4.00 |
| 4.00～4.30 | ||||
| 4.30～4.88 | ||||
| USS 11/8 | 31.57～32.51 | 69.67～70.61 | 3.45～4.88 | 3.45～4.00 |
| 4.00～4.30 | ||||
| 4.30～4.88 | ||||
| USS 11/4 | 34.75～35.69 | 76.02～76.96 | 3.45～4.88 | 3.45～4.00 |
| 4.00～4.30 | ||||
| 4.30～4.88 | ||||
| USS 13/8 | 37.85～39.24 | 82.30～83.69 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 | ||||
| USS 11/2 | 41.02～42.42 | 88.65～90.04 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 | ||||
| USS 15/8 | 44.20～45.59 | 95.00～96.39 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 | ||||
| USS 13/4 | 47.37～48.77 | 101.35～102.74 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 | ||||
| USS 17/8 | 50.55～51.04 | 107.70～109.09 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 | ||||
| USS 2 | 53.72～55.12 | 114.05～115.44 | 3.89～5.41 | 3.89～4.40 |
| 4.40～5.00 | ||||
| 5.00～5.41 |
