Environmental requirement
WTGS(wind turbine generator system) foundation anchor bolt operating temperature range -40℃～50℃, relative humidity≤ 95%
Outdoor weather conditions for WTGS foundation anchor bolts include air humidity, salinity and dust bowl area.
Appearance
Visual and rule measurement inspection shall be used to inspect apperance of nuts according to GB/T5779.2-2000 “Fasteners-Surface discontinuities-Nuts”, satisfying Table 1.
| Nut grades | Inspection standard | Voids | Quenchcracks | Seams | Forging cracks | Folds |
| 810 | GB/T 5779.2-2000 | Depth,h≤0.25mm | Quench cracks of any depth, any length, or in any location shall not be permitted. | Depth≤0.05D | not more than two forging cracks, neither of which exceed a depth of 0.05D | permitted |
Table 1. Surface Discontinuities on Nuts
D——nominal thread diameter
Dimensions
Dimensions and tolerances of nuts shall conform to GB/T 6170-2000 “Hexagon nuts,style 1” regulations. According to GB/T 6170-2000, the nut’s thickness m value shall be 1.2-1.3 times of the “m” from the TABLE 1 of GB/T 6170-2000.Specific values are shown in Table 2.
Table 2 Thickness of Nuts
unit：mm
| Thread Dimensions(d) | M30 | M36 | M42 | M48 | M56 | M64 | ||
| Pintch P | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | ||
| GB/T6170-2000 | TH m | max | 25.6 | 31.0 | 34.0 | 38.0 | 45.0 | 51.0 |
| min | 24.3 | 29.4 | 32.4 | 36.4 | 43.4 | 49.1 | ||
| Q/AYLT 06-2016 | THm | max | 31.5 | 38.5 | 42.0 | 47.0 | 56.0 | 63.0 |
| min | 30.0 | 37.0 | 38.0 | 45.5 | 54.0 | 61.0 | ||
Steel Materials
Materials of nuts and washers shall conform to Table 4. Choosing of any other materials shall be approved by purchaser.
Table 4 Anchor bolts, nuts, washers materials
| Commodity | Grade | Raw materials grade | Standard |
| Nuts | grade 8、grade 10 | 35CrMo or 45 | GB/T 3077-2015 or GB/T 699-1999 |
| Washers | HRC35-45 | 45 | GB/T 699-1999 |
Manufacturing Methods
Nuts shall be hot-forged from hot-rolled steel round bars,internal threads shall be formed by screws.
Surface
Before coating on nuts and washers, clean the surface, remove oxide scale, rust, oil stain, to guarantee grade Sa2.5 cleanliness. Surface treatment and formula shall be left at the discretion of the manufacturer. Grease corrosion protecting method on nuts and washers is not included in this regulation.
Inspection
Inspection items and methods for nuts and washers shall conform to Table 6.
Table 6 Inspection item, sampling and methods
| Sr. | Test Items | Sampling | Type inspection | Delivery Inspection | Standard |
| 1 | Appearance | 3/same batch | √ | Test documents | GB/T 3103.1-2002 GB/T 3103.3-2000GB/T 5779.2-2000 |
| 2 | Dimension | 3/same batch | √ | Test documents | GB/T 6170-2000 GB/T 3103.3-2000 GB/T 196-2003GB/T 197-2003 |
| 3 | Composition | 3/same batch | √ | Test documents | GB/T 3077-2015GB/T 699-1999 |
| 4 | Cone roof load test | 3/same batch | √ | Test documents | GB/T 3098.1-2010 |
| 5 | Hardness | 3/same batch | √ | Test documents | GB/T 230.1-2009 GB/T 4340.1-2009 |
| Note: 1.”Same batch” refers to same batch of raw materials and same batch of heat treatment.2.”Same scheme” refers to one scheme for a specified property. | |||||
3.”Same product” refers to a product model of same dimension from one specified manufacturer.
4.Test items and methods can be performed as per purchasers’ requirements.
Marking
5.1 Marking
Marking methods for nuts and washers shall perform according to regulations, including:
a)Identification of manufacturer;
b)Property class;
Post time: May-21-2019