Bend Test and Sling Ratings

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Questions and Answers

What does the bend test primarily evaluate in a material?

The electrical conductivity of the material

The tensile strength of the material

The thermal resistance of the material

The ductility or resistance to fracture of the material (correct)

In which area is it preferable to mark lifting equipment?

Any area that is easily accessible

Anywhere on the equipment to maximize visibility

In areas subjected to high stress for durability

A non-load bearing or low-stress area (correct)

What is the main purpose of performing a bend test on welds?

To check for corrosion resistance in the weld

To determine the color of the weld

To evaluate the cost-effectiveness of the welding process

To ensure the weld has properly fused to the parent metal (correct)

Why should marking on lifting equipment be done with care?

To prevent the introduction of stress raisers Signup and view all the answers

Which of the following is NOT a recommended method for marking lifting equipment?

Applying removable stickers Signup and view all the answers

What is a significant drawback of using the trigonometric method for rating multipurpose slings?

It can result in misjudging angles, risking overload. Signup and view all the answers

Which method is generally recommended for slings intended for multipurpose use?

Uniform load method. Signup and view all the answers

How is the working load limit (WLL) calculated for a three leg sling?

3 x WLL of a single leg x cos β. Signup and view all the answers

What is the primary advantage of the uniform load method compared to the trigonometric method?

It eliminates the need for tables and simplifies calculations. Signup and view all the answers

In which scenario would it be acceptable to use the trigonometric method for sling rating?

When national standards allow deviations. Signup and view all the answers

What is the primary purpose of heat treatment in the manufacture of chains?

To increase the chains' ductility and toughness Signup and view all the answers

What grade of chain sling has become obsolete for lifting applications?

Wrought iron chain Signup and view all the answers

Which of the following statements is true regarding chain slings?

Modern chain slings are primarily made of grade 8. Signup and view all the answers

What characteristic should medium tolerance chain have for effective use as a sling?

It needs to be more ductile to withstand shock loading. Signup and view all the answers

What should be avoided in the lifting of loads with chain slings?

Using worn-out or damaged chain slings Signup and view all the answers

Which statements about the production of chains is correct?

The sides of chain links produced by machine have slight curves. Signup and view all the answers

What potentially hazardous condition can occur if chain slings are not used correctly?

Damage to the chain and serious incidents can occur. Signup and view all the answers

What is the primary factor that affects the working load limit (WLL) of a wire rope sling?

The tensile strength of the rope Signup and view all the answers

Which type of chain sling is becoming increasingly popular for lifting applications?

Grade 10 chain Signup and view all the answers

How does a steel core rope compare to a fiber core rope in terms of breaking load?

It has a marginally higher breaking load. Signup and view all the answers

What is a benefit of using double part legs in a wire rope sling?

They offer a greater bearing area for the load. Signup and view all the answers

Which method is preferred for rating multipurpose slings?

The uniform load method Signup and view all the answers

What should be assessed by a Competent Person regarding slings?

The SWL to be marked on the sling Signup and view all the answers

At what maximum angle of inclination can a sling be rated for safe use?

45° Signup and view all the answers

What is a disadvantage of using double part legs in a wire rope sling?

They are more costly. Signup and view all the answers

What happens to the flexibility of a rope with a steel core compared to a fiber core?

It becomes less flexible. Signup and view all the answers

What type of splice should be avoided for lifting purposes due to its tendency to undo?

Tuck splice Signup and view all the answers

What is a commonly used gripping device for making temporary eyes in wire ropes?

Bulldog grip Signup and view all the answers

Why are bulldog grips not recommended for the manufacture of slings?

They do not maintain an acceptable level of safety. Signup and view all the answers

When producing an endless sling with thimbles, how should the thimbles be sized relative to the rope diameter?

Two or three sizes larger than the rope diameter Signup and view all the answers

What is the impact of bending the rope around a tight radius when producing sling legs?

It reduces the WLL by approximately 25%. Signup and view all the answers

What is a common method of fitting sockets and fork ends to wire rope?

Compression process or bonding process Signup and view all the answers

In the production of sling legs, what must be done to make the thimble fit the rope?

Serve the rope with wire or spun yarn Signup and view all the answers

What is the characteristic of sling legs produced as single parts compared to those produced using an endless method?

Endless method sling legs have a greater WLL. Signup and view all the answers

What is a primary benefit of using a rough terrain crane?

Optimized for lifting heavy loads on uneven ground. Signup and view all the answers

Which type of mobile crane is typically employed in confined urban environments?

City crane Signup and view all the answers

What must be considered when designing lifting sets for offshore containers?

Dynamic motions experienced during lifting. Signup and view all the answers

What purpose does a top leg (forerunner) serve in lifting sets for containers?

To prevent workers from having to stand on top of the container. Signup and view all the answers

What is a key feature of truck-mounted cranes?

Fast relocation from one job site to another. Signup and view all the answers

Which crane is specifically suited for factory use where small loads need to be transported?

Yard crane Signup and view all the answers

What is the primary safety consideration when using mobile cranes?

Implementing proper weight distribution and stability. Signup and view all the answers

Which mobile crane type is known for its ability to function well in areas with uneven ground?

Rough terrain crane Signup and view all the answers

What distinguishes an under-slung bridge crane from a top running bridge crane?

It runs on the bottom flanges of the cranes tracks. Signup and view all the answers

Which type of crane is characterized by running on a low-level track, typically at ground level?

Portal bridge crane Signup and view all the answers

What is a common method for securing crane or track rails?

Intermittent welding and clamping Signup and view all the answers

Which of the following crane types can have multiple cranes running on parallel tracks for load transfer?

Under-slung bridge crane Signup and view all the answers

What is the primary function of bridge and gantry cranes?

Transporting loads over a designated area Signup and view all the answers

What is a notable feature of a semi-portal bridge crane?

Combines features of different crane types Signup and view all the answers

Which aspect is critical for the stability of an underslung crane?

The way it is mounted on the bottom flanges of the beam Signup and view all the answers

What is a critical consideration when welding crane or track rails?

The rail must be securely clamped or welded to avoid cracking. Signup and view all the answers

What is a primary feature of an all terrain crane?

It is designed to travel over and relocate between different types of terrain. Signup and view all the answers

What is the main advantage of a loader crane?

It eliminates the need for separate lifting equipment by integrating with a truck. Signup and view all the answers

What is a distinctive characteristic of tower cranes?

They rise hundreds of feet into the air and have a significant outreach. Signup and view all the answers

What defines an offshore pedestal crane?

It is designed to transfer materials and personnel between marine vessels and structures. Signup and view all the answers

Which statement accurately describes safety procedures in crane operation?

Regular inspection and maintenance are crucial for safe operation. Signup and view all the answers

In which scenario is using a loader crane most advantageous?

For delivering goods directly to a construction site without additional equipment. Signup and view all the answers

What critical role do tower cranes fulfill at construction sites?

They lift various building materials including steel and concrete. Signup and view all the answers

Which of the following is NOT a typical use for an offshore pedestal crane?

Moving heavy machinery on construction sites. Signup and view all the answers

Study Notes

Bend Test

A qualitative test determining material ductility or fracture resistance by creating a mid-point bend without breaking.
Applicable to metals, polymers, and plastics; commonly used for testing welds to ensure proper fusion and absence of defects.

Marking Lifting Equipment

Equipment should be marked using plates, metal tabs, textile labels, or direct stamping in low-stress areas to ensure visibility.
Identification should remain intact even if the main marking is lost, recommending multiple marking methods for redundancy.
Care is necessary when re-marking to avoid inducing stress raisers that could compromise mechanical properties.

Sling Rating Methods

The uniform load method minimizes error by eliminating the need for operators to estimate angles, now preferred for safety and simplicity.
The trigonometric method may still be applicable per national standards but mainly for single-purpose slings.
Working Load Limits (WLL) calculation varies by the number of sling legs and angles, with specific equations for different configurations.

Wire Rope Slings

The WLL of wire rope slings depends on rope size, tensile strength, core type, number of parts, and sling geometry.
Steel core ropes exhibit higher breaking loads than fiber-core counterparts, offering more resistance to crushing but less flexibility.
Multi-leg slings increase flexibility and bearing area but are more costly and typically used for high-capacity loads.

Chain Slings

Chain is produced by shaping steel bars into links through automated processes, followed by heat treatment for optimal material properties.
Chain slings should be constructed from grade 8 or grade 10 materials; mild steel and wrought iron chains are obsolete due to safety standards.
Modern chains need to be medium tolerance and ductile, designed to withstand shock loading without excessive wear.

Safety Considerations

Use of clamp-type grips for wire rope should be avoided as they fail to provide consistent safety levels.
Manufacturer's guidelines for sockets and fork ends must be followed for safe use; they can be bonded or compressed onto the rope.
Maximum angle of inclination for rated slings is 60°, with safety assessments needed to establish appropriate SWL in various conditions.

Crane Types and Functions

All Terrain Crane:
- Commonly used for traveling over diverse terrains
- Capable of swift relocation on highways between job sites
Loader Crane:
- Mounted on trucks, facilitates loading and unloading goods
- Eliminates the need for additional lifting equipment like forklifts or telehandlers
Tower Crane:
- Essential at major construction sites, capable of lifting heavy materials
- Can reach significant heights and has a large outreach for materials like steel and concrete
Offshore Pedestal Crane:
- Used to transfer materials and personnel between marine vessels and offshore structures
- Characterized by its pedestal-mounted design

Crane Mechanisms and Designs

Underslung Cranes:
- Operate on the bottom flanges of beams, mounted either on carrier beams or directly on support columns
Bridge and Gantry Cranes:
- Designed for lifting and transporting loads over a designated area
- Typically powered electrically, with manual options available

Specific Types of Bridge and Gantry Cranes

Top Running Bridge Crane:
- Runs on top of rails integrated into its supporting structure
Under-Slung Bridge Crane:
- Operates on the lower flanges, allowing potential for cantilever design
Portal Bridge Crane:
- Utilizes a ground-level track with legs supporting the bridge, which may feature cantilevers
Semi-Portal Bridge Crane:
- Combines features of top running and portal bridge cranes, with cantilevering options supported by legs

Offshore Container Considerations

Offshore Containers:
- Designed with specific lifting features like pad eyes for secure lifting
- Types include waste skips, baskets, and machinery skids
Safety Measures:
- Enhancement factors must be calculated for lifting sets due to offshore dynamics
- Use of a top leg (forerunner) is essential to minimize risk during container lifting

Mobile Cranes Overview

Yard Crane:
- Utilized in factories for handling small loads on its platform
Truck-Mounted Crane:
- Versatile design that allows rapid movement between jobs
Rough Terrain Crane:
- Built for uneven ground, can lift and transport loads while moving
City Crane:
- Tailored for operation in confined urban spaces, addressing space limitations

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Description

This quiz covers essential concepts related to bend tests for material ductility and fracture resistance. Additionally, it addresses the marking of lifting equipment and the various methods used for rating slings, emphasizing safety and compliance. Aimed at professionals working in material testing and lifting operations.