science

Steam hammer

Steam hammer is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Steam hammer rather than just read about it. In short: A steam hammer, also called a drop hammer, is an industrial power hammer driven by steam that is used for tasks such as shaping forgings and driving piles. Typically the hammer is attached to a piston that slides within a fixed cylinder, but in some designs the hammer is attached to a cylinder that slides along a fixed piston.

Key takeaways

Steam hammer belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Steam hammer to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Steam hammer from memory before moving on to harder problems.

Reference excerpt

A steam hammer, also called a drop hammer, is an industrial power hammer driven by steam that is used for tasks such as shaping forgings and driving piles. Typically the hammer is attached to a piston that slides within a fixed cylinder, but in some designs the hammer is attached to a cylinder that slides along a fixed piston. The concept of the steam hammer was described by James Watt in 1784, but it was not until 1840 that the first working steam hammer was built to meet the needs of forging increasingly large iron or steel components. In 1843 there was an acrimonious dispute between François Bourdon of France and James Nasmyth of Britain over who had invented the machine. Bourdon had built the first working machine, but Nasmyth claimed it was built from a copy of his design. Steam hammers proved to be invaluable in many industrial processes. Technical improvements gave greater control over the force delivered, greater longevity, greater efficiency and greater power. A steam hammer built in 1891 by the Bethlehem Iron Company delivered a 125-ton blow. In the 20th century steam hammers were gradually displaced in forging by mechanical and hydraulic presses, but some are still in use. Compressed air power hammers, descendants of the early steam hammers, are still manufactured.

Mechanism A single-acting steam hammer is raised by the pressure of steam injected into the lower part of a cylinder and drops under gravity when the pressure is released. With the more common double-acting steam hammer, steam is also used to push the ram down, giving a more powerful blow at the die. The weight of the ram may range from 225 to 22,500 kg (500 to 50,000 lb). The piece being worked is placed between a bottom die resting on an anvil block and a top die attached to the ram (hammer).

Hammers are subject to repeated concussion, which could cause fracturing of cast iron components. The early hammers were therefore made from a number of parts bolted together, which made it cheaper to replace broken parts, and also gave it a degree of elasticity that made fractures less likely.A steam hammer may have one or two supporting frames. The single frame design lets the operator move around the dies more easily, while the double frame can support a more powerful hammer. The frame(s) and the anvil block are mounted on wooden beams that protect the concrete foundations by absorbing the shock. Deep foundations are needed, but a large steam drop hammer will still shake the building that holds it. This may be solved with a counterblow steam hammer, in which two converging rams drive the top and bottom dies together. The upper ram is driven down and the lower ram is pulled or driven up. These hammers produce a large impact and can make large forgings. They can be installed with smaller foundations than anvil hammers of similar force. Counterblow hammers are not often used in the United States, but are common in Europe. With some early steam hammers an operator moved the valves by hand, controlling each blow. With others the valve action was automatic, allowing for rapid repetitive hammering. Automatic hammers could give an elastic blow, where steam cushioned the piston towards the end of the down stroke, or a dead blow with no cushioning. The elastic blow gave a quicker rate of hammering, but less force than the dead blow. Machines were built that could run in either mode according to the job requirement. The force of the blow could be controlled by varying the amount of steam introduced to cushion the blow. A modern air/steam hammer can deliver up to 300 blows per minute.

History

Concept The possibility of a steam hammer was noted by James Watt (1736–1819) in his 28 April 1784 patent for an improved steam engine. Watt described "Heavy Hammers or Stampers, for forging or stamping iron, copper, or other metals, or other matters without the intervention of rotative motions or wheels, by fixing the Hammer or Stamper to be so worked, either directly to the piston or piston rod of the engine." Watt's design had the cylinder at one end of a wooden beam and the hammer at the other. The hammer did not move vertically, but in the arc of a circle. On 6 June 1806 W. Deverell, engineer of Surrey, filed a patent for a steam-powered hammer or stamper. The hammer would be welded to a piston rod contained in a cylinder. Steam from a boiler would be let in under the piston, raising it and compressing the air above it. The steam would then be released and the compressed air would force the piston down.

In August 1827 John Hague was awarded a patent for a method of working cranes and tilt-hammers driven by a piston in an oscillating cylinder where air power supplied the motive force. A partial vacuum was made in one end of a long cylinder by an air pump worked by a steam engine or some other power source, and atmospheric pressure drove the piston into that end of the cylinder. When a valve was reversed, the vacuum was formed in the other end and the piston forced in the opposite direction. Hague made a hammer to this design for planishing frying pans. Many years later, when discussing the advantages of air over steam for delivering power, it was recalled that Hague's air hammer "worked with such an extraordinary rapidity that it was impossible to see where the hammer was in working, and the effect was seemed more like giving one continuous pressure." However, it was not possible to regulate the force of the blows.

Invention

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Steam hammer

Start with the simplest possible case. Write down what Steam hammer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Steam hammer before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Steam hammer ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Steam hammer

In research: Steam hammer appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Steam hammer in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Steam hammer is common in secondary-school and first-year university syllabi. It links to neighbouring topics French inventions, Hammers, Industrial machinery, so understanding it makes those chapters shorter.
In everyday life: Look for Steam hammer outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Steam hammer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Steam hammer means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Steam hammer out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Steam hammer in simple terms?

Why does Steam hammer matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Steam hammer?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Steam hammer.