RR-C-271 Chains And Attachments, Carbon And Alloy SteelThis specification covers carbon and alloy steel chain of commercial quality together with the attachments most commonly used with this chain.

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RR-C-271F

3.4.4 Type V, hooks. The hooks shall be forged from alloy steel as specified in 3.1.1.2.1. Class 1, 2, 3, and 6 hooks shall be used with type I alloy chain.

3.4.4.1 Ductility. Hooks shall be sufficiently ductile so that, when fractured, the fractured member shall show a permanent distortion before breaking. The throat opening shall show a permanent bend of not less than 15 degrees.

3.4.4.1.1 Finish. Hooks shall be as specified in 3.2.1.3.

3.4.4.2 Class 1, eye slip hook. The eye slip hooks shall have the eye parallel to the hook, shall be similar to figure 19, and shall be in accordance with the physical requirements as shown in table XV.

FIGURE 19. Type V, class 1, eye slip hook. TABLE XV. Type V, class 1, eye slip hook.

Size of chain (nominal) (inch)

Weight each (approx) (pounds)

Working load limit (pounds)

Proof load (min) (pounds)

Breaking load

(min) (pounds)

1/4

3/8

1/2

5/8

3/4

0.4

1.0

2.5

3.1

6.0

3,600

6,400

11,400

17,800

25,650

7,200

12,800

22,800

35,600

51,300

14,400

25,600

45,600

71,200

102,600

3.4.4.3 Class 2, eye grab hooks. The eye grab hooks shall have the eye parallel to the hook, shall be similar to figure 20, and shall be in accordance with the physical requirements as shown in table XVI.