色戒时长完整版,亚洲国产一区二区三区精品,久久久久久久精彩视频,怡红院av亚洲一区二区三区h,艳情五月,国产亚洲成av人在线观看导航,男女午夜免费视频

Main Products
Products Grade: 51B20
Specifications: φ5.5~42mm
Applied Standard:  agreement
Characteristics: This product is used to produce fastener for steel structure of class 10.9.
Applications: Common partsCommon fastenerHigh strength fastener
Use of Products: 51B20 is a steel grade which used to produce high strength bolt of class 10.9 .This product has characteristics of uniform-chemical composition, low percentage of harmful elements, high purity, slight decarburization, good surface quality. After spheroidize annealing, this product has the characteristics of good cold heading properties. And the product has excellent hardenability.