Engineering · Past QCAA questions All past questions
2022 · Section 2 · Short response

Question 12

[4 marks] Simple familiar
Topic guidesPremiumTopic guide 10 · Applications by carbon contentTopic guide 10 · What the exam asks
Game plansPremiumTemplate T6 Recall ladder4.3 Naming the steel and its structure
The question

State four industrial applications for carbon steel with 0.15% to 0.30% carbon content.

Watch the situation first

Steel with 0.15% to 0.30% carbon is low-carbon steel, soft enough to roll, press and draw

Watch the orange window on the carbon axis move from the 2019 band names to the 2025 ones, then watch the microstructure and the applications it leads to.

In 2022, 0.15% to 0.30% carbon steel was mild steel The 2025 syllabus calls it low-carbon steel, 0.07% to 0.30% It is mostly ferrite, with about 18% to 36% pearlite Soft, ductile and tough, so it is rolled, pressed and drawn 20192025 lowmildmediumhigh, from 0.60% low carbonmediumhigh, from 0.60% 0.15% to 0.30% C 00.20.40.60.81.0Carbon (%) Under the microscope 0.15% C: about 18% pearlite 0.30% C: about 36% pearlite The 2025 low-carbon list Automobile body partsductile, so sheet presses to shape Wire productsductile, so it draws through dies Structural plates and sectionstough, and easy to roll and weld Seamless tubesductile, so it forms into a tube Boiler platetough, and easy to roll and weld Stampings and forgings: accepted in 2022, now on the medium-carbon list

The 0.15% to 0.30% window was the whole mild band in 2019 and sits entirely inside the 2025 low-carbon band. Mostly ferrite means soft, ductile and tough, which is why every application on the list is formed into shape.

Now for the engineering

Pick four applications and see how the 2022 marker and the 2026 list score them

Choose four. Each one is checked twice, against the 2022 marking guide, which was written to the 2019 lists, and against the 2025 syllabus list you will be marked on in 2026. The two do not always agree.

Applications

Your four2022 marker2026 list
Marks
QCAA marking guide · 4 marks

Work through the solution one mark at a time

One mark per correct application, four in all. QCAA’s sample answer is a numbered list of four words or phrases. Try each step yourself before you reveal it.

Application · Step 11 mark

Place the carbon first. 0.15% to 0.30% was mild steel when this paper was set, and it is low-carbon steel now. Then recall the list.

QCAA’s sample: “1. Structural plates”

Still on the 2025 list, as structural plates and sections.

Marker: provides a correct industrial application

Application · Step 21 mark

QCAA’s sample: “2. Stampings”

Accepted in 2022. The 2025 syllabus lists stampings and forgings under medium-carbon steel, so do not use it for a low-carbon question in 2026.

Marker: provides a second correct industrial application

Application · Step 31 mark

QCAA’s sample: “3. Forgings”

Same story as stampings. It earned the mark in 2022 and it is a medium-carbon application on the 2025 list.

Marker: provides a third correct industrial application

Application · Step 41 mark

QCAA’s sample: “4. Seamless tubes”

The guide’s notes also accept “structural sections” and “boiler plate”, and they say that industrial applications “do not include” wire products, gears, crankshafts, shafts and axles, train rails, wheels and axles, “or uses requiring extreme hardness, e.g. punches and cutting tools”. Wire products are on the 2025 low-carbon list, so that exclusion no longer holds. For 2026, answer from the 2025 list.

1. Automobile body parts   2. Structural plates and sections   3. Seamless tubes   4. Boiler plate

Wire products also works in 2026. No reasons are needed, because state asks for the items and nothing more.

Marker: provides a fourth correct industrial application

Putting it all together

Each phrase of the question gave you something

“State”
The items and nothing more. No reasons, no properties, no working.
“four industrial applications”
Four marks, one per item. A fifth earns nothing.
“carbon steel with 0.15% to 0.30% carbon content”
The question never names the steel. Place the range in its band first, low-carbon steel in 2026, then recall that band’s list.
What makes this simple familiar

QCAA did not publish a band for this question. It reads as simple familiar, because it is four items of recall from one syllabus list, with no explanation asked for. This state-four opener has not appeared since 2023. In 2026 the same list turns up in multiple choice and inside the explain and compare questions, and mild steel is now called low-carbon steel, 0.07% to 0.30% carbon.

If I had to guess where you might lose marks, it would be reaching for the medium-carbon list. Gears, shafts, crankshafts, axles and train rails sound like ordinary steel jobs, and the 2022 guide rejected every one of them. In 2026, stampings and forgings join that group, so the safe answers are the five on the 2025 low-carbon list.

Only mark this done when you could do it without help. Reading the solution does not count.

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Question wording, any figures and marking-guide steps are from the 2022 QCAA Engineering external assessment, © State of Queensland (QCAA) 2022, licensed under CC BY 4.0, and have been adapted, except where a third-party source is named. Tangent Tuition is not affiliated with the QCAA.

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