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Effect of section thickness on microstructure and mechanical properties of compacted graphite iron for diesel engine applications · 10.1016/j.heliyon.2021.e05930

Name: Verified Rigor Record — Effect of section thickness on microstructure and mechanical properties of compacted graphite iron for diesel engine applications · 10.1016/j.heliyon.2021.e05930
Item: Effect of section thickness on microstructure and mechanical properties of compacted graphite iron for diesel engine applications · 10.1016/j.heliyon.2021.e05930
Rating: 72
Author: Αlpha¹

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Αlpha¹ Editorial

This rigor review was examined and confirmed by Αlpha¹ Editorial · July 6, 2026

Αlpha¹ Rigor Review

Rigor Reviewed

WARN

Warnings to address · Observational Study

Eight dimensions — click a segment for details

Critical

High-priority

Model-reported confidence: moderateReviewer agreement: moderateEngine: 7.6.0Source: full text

Not verified in this report

No reported statistical tests were found to recompute.
No data or code availability links were detected to verify.

This Αlpha¹ Rigor Review uses AI Rigor Reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

The paper presents a well-motivated materials science study comparing microstructure and mechanical properties of compacted graphite iron cast at different section thicknesses and pouring durations. Major strengths include a clear scientific premise, adequate replication within the same casting (n=3 tensile specimens per condition), and a complete description of the experimental procedure. Key weaknesses are the lack of any measure of variability (SD, error bars) on reported means, the absence of inferential statistics, a vague data availability statement, lack of vendor information for reagents and software, and no dedicated limitations discussion.

The evaluation covered six applicable dimensions out of eight; biological variables and ethical approvals were not applicable as the study uses only inorganic materials. The three independent reviewers largely agreed on the key issues, though one reviewer diverged on study design (rating it not applicable) and statistical analysis (rating it not applicable). The citation verification found no retracted or missing references, and no statistical tests were available for verification.

10 major claims checked against the paper's own evidence: all adequately supported.

Rigor

Eight Dimensions1 pass · 5 warn

10 major claims1 partial9 supported

The introduction cites 19 references covering compacted graphite iron properties, cooling rate effects, and prior work on heat treatment and holding time. It explicitly states that previous work studied heat-treated CGI, but engine blocks are used as-cast, motivating the current study. The rationale is clear: section thickness and pouring duration affect cooling rate, which determines microstructure and mechanical properties.

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 90% conf

The paper adequately establishes the scientific premise through cited prior work on compacted graphite iron, cooling rate effects, and the known importance of section thickness.

Evidence

direct quote[Introduction, paragraph 1-3]

“Compacted graphite cast iron composed of an iron matrix that consists of one or mixture of iron phases (pearlite, ferrite, austenite, etc.) and graphite of worm shape. Factors controlling compacted cast iron microstructure include alloying elements content, cooling rate, and therefore, the supplement heat treatment after solidification [3].”

direct quote[Introduction, final paragraph]

“The aim of the current work is to check the effect of cooling rate on vermicular graphite cast iron through solidification of various casting section thickness with two different pouring duration (10.5 and 17.5 min respectively).”

absence[Introduction]

No explicit discussion of limitations of prior work is found.

PASSReviewer 2· 95% conf

The paper clearly establishes its scientific foundation by citing prior work, providing a logical rationale linking cooling rate to microstructure and properties, and addressing a gap in prior research.

Evidence

direct quote[Introduction, paragraphs 1-4]

direct quote[Introduction, final paragraph]

“In previous work [14], the authors studied the effect of heat treatment and holding time or pouring duration on the identical compacted graphite iron. However, internal-combustion engine blocks are employed in the as-cast condition. Therefore, the as-cast microstructures should be investigated.”

PASSReviewer 3· 90% conf

The scientific premise is adequately established: prior research on compacted graphite iron (CGI) is cited, the rationale linking cooling rate, wall thickness, and microstructure is logically laid out, and gaps in prior work (as-cast vs. heat-treated) are addressed.

Evidence

paraphrase[Introduction, paragraphs 1–4]

“The introduction cites multiple references (e.g., Guesser, Dawson, Qiu, Lacaze, Megahed) demonstrating the effects of cooling rate, alloying, and section thickness on microstructure and properties.”

direct quote[Introduction, final paragraph]

“In previous work [], the authors studied the effect of heat treatment and holding time or pouring duration on the identical compacted graphite iron. However, internal-combustion engine blocks are employed in the as-cast condition. Therefore, the as-cast microstructures should be investigated.”

direct quote[Introduction, final sentence]

As an observational metallurgical study, randomization, blinding, and biological replicate distinction are not applicable. An a priori power analysis is not reported, and no sample-size justification is given. Inclusion/exclusion criteria for tensile specimens are not pre-specified (only that three samples per thickness were machined). Outlier handling is not discussed. No independent replication of key findings (e.g., by a different foundry or researcher) is reported or mentioned. The study does state that three tensile specimens per condition were tested, which provides some replication within the same casting. Controls are not applicable (no comparator group beyond the different thicknesses).

Sub-criteria

controlsN/A

power analysisNOT REPORTED

blinding levelsN/A

outlier handlingNOT REPORTED

randomization unitN/A

inclusion exclusionNOT REPORTED

randomization methodN/A

replicate distinctionN/A

independent replicationNOT REPORTED

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

The study design is a controlled materials experiment with two pouring durations and four section thicknesses, but lacks several classical design rigor elements such as randomization, blinding, and power analysis.

Evidence

direct quote[Methods, Section 2.3 Tensile test]

“For each thickness, three repetition tensile specimens were machined for testing.”

absence[Methods, Section 2.1]

No randomization method is mentioned for sample assignment.

absence[Methods and Results]

No blinding or power analysis is reported.

N/AReviewer 2· 95% conf

The study is a materials science experiment with controlled variables; none of the standard biomedical design sub-criteria (randomization, blinding, power analysis, etc.) are applicable or engaged.

Evidence

direct quote[Methods, Section 2.1]

“The compacted graphite iron (CGI) was produced using step block casting in green sand with four different thicknesses 5, 10, 15 and 20 mm thick steps”

direct quote[Methods, Section 2.3]

“For each thickness, three repetition tensile specimens were machined for testing.”

WARNReviewer 3· 85% conf

The study design is mostly descriptive and observational; randomization is not applicable, but several key design elements for a materials characterization study are missing or inadequately reported: no explicit power analysis, no pre-specified inclusion/exclusion criteria, no outlier handling, and no independent replication.

Evidence

absence[Methods, sections 2.1–2.3]

No power analysis or sample-size justification is reported.

direct quote[Methods, section 2.3]

“For each thickness, three repetition tensile specimens were machined for testing.”

absence[Entire paper]

No mention of independent replication by an external group or in a separate series of experiments.

All sub-criteria (sex, age/weight/health, species/strain, housing, demographics) pertain to biological subjects or human participants. This is a materials science study on cast iron; no living organisms or human subjects were used.

Sub-criteria

demographicsN/A

sex reportedN/A

sex justifiedN/A

age weight healthN/A

housing conditionsN/A

species strain sourceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 95% conf

This study involves only inorganic materials (cast iron), with no biological subjects, organisms, or human participants.

N/AReviewer 2· 95% conf

The study is on a non-living material (compacted graphite iron); no biological variables such as sex, age, or species are relevant.

Evidence

direct quote[Title and Introduction]

“Effect of section thickness on microstructure and mechanical properties of compacted graphite iron for diesel engine applications”

N/AReviewer 3· 100% conf

The study involves compacted graphite iron castings, not biological organisms or human subjects; therefore, biological variables are not applicable.

Evidence

direct quote[Title, Introduction, Methods]

“Effect of section thickness on microstructure and mechanical properties of compacted graphite iron for diesel engine applications”

The paper describes the production and mechanical testing of compacted graphite iron castings. No human or animal subjects were used, no human tissue or samples were collected, and no non-public identifiable data were handled. Therefore, ethical-approval criteria are not applicable.

Sub-criteria

iacuc statementN/A

informed consentN/A

irb ethics statementN/A

regulatory complianceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 95% conf

The study involves only industrial materials (cast iron) with no human or animal subjects, tissue, or non-public identifiable data, so ethics approvals are not required.

N/AReviewer 2· 95% conf

The study does not involve human or animal subjects, tissues, or non-public identifiable data, so no ethics approval is required.

Evidence

absence[Entire paper]

The study is entirely on a metallic material; no human or animal subjects are involved.

N/AReviewer 3· 100% conf

The study involves only cast iron metallurgy, with no human participants, animal subjects, human tissue, or non-public identifiable data; no ethical approval is needed.

Evidence

paraphrase[Title and Methods]

“The entire study is on compacted graphite iron castings, their microstructure, and mechanical properties.”

The paper lists the alloying elements added (ferrotitanium with 80% Ti, pure tin, pure copper) and the etching solution (Nital 2%). However, no supplier or catalog numbers are provided. The optical microscope is identified (Zeiss Axiotech), but the image analysis program is only mentioned as 'image analysis program' without a name or version. This is a minor gap that prevents full reproducibility.

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedINADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 75% conf

The paper identifies the starting materials (GGG70 pig iron, ferrotitanium, tin, copper) and equipment, but software tools and some reagent details are underreported.

Evidence

direct quote[Methods, Section 2.2]

“Throughout this analysis; image analysis program and optical metallography were used to determine the percentage values of carbides, pearlite and martensite.”

direct quote[Tables 1 and 2]

“Table 1 Chemical composition of pig iron GGG70. Table 2 Chemical composition of compacted graphite iron.”

WARNReviewer 2· 85% conf

Key reagents (alloying elements, etching solution) are identified by composition but lack vendor/catalog numbers; the image analysis software used is not named.

Evidence

direct quote[Methods, Section 2.1]

“1.5 kg ferrotitanium alloy with 80% Ti, 2) 0.5 kg pure tin (Sn) free of lead to enhance the mechanical properties and 3) 1% pure copper (Cu).”

direct quote[Methods, Section 2.2]

“Throughout this analysis; image analysis program and optical metallography were used to determine the percentage values of carbides, pearlite and martensite.”

WARNReviewer 3· 85% conf

Key resources are partially identified: the base pig iron (GGG70) and chemical compositions are reported, but no vendor/catalog numbers are provided for the furnace, optical microscope, or universal testing machine, and no software version is identified for the image analysis program.

Evidence

direct quote[Table 1 and Table 2]

“The used spheroidal pig iron is (GGG70) with the chemical composition in [Table 1].”

direct quote[Methods, section 2.2]

“Throughout this analysis; image analysis program and optical metallography were used to determine the percentage values of carbides, pearlite and martensite.”

The paper reports mean tensile strength values and Brinell hardness data, but no statistical tests (t-test, ANOVA, etc.) are performed or named. No p-values, confidence intervals, or effect sizes are reported. Software for analysis is not identified. Data are presented as means (presumably from three tensile specimens), but individual data points are not shown, and error bars are not defined (no SD/SEM). The paper uses descriptive comparison rather than inferential statistics. The mathematical_plausibility sub-criterion is not_applicable because no test statistics or percentages with Ns are provided to verify (mean values are from continuous measurements).

Sub-criteria

tests namedNOT REPORTED

exact p valuesNOT REPORTED

effect sizes ciNOT REPORTED

data presentationINADEQUATE

software identifiedNOT REPORTED

assumptions verifiedNOT REPORTED

mathematical plausibilityN/A

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

The paper reports mean values and hardness data but does not perform any inferential statistical tests, nor reports p-values, effect sizes, or confidence intervals.

Evidence

absence[Results & discussions]

No statistical tests are performed or named.

direct quote[Results, Section 3.3]

“The tensile strength for sample number 1 has 716 MPa and for sample number 2 has 748 MPa.”

absence[Methods]

No software for statistical analysis is identified.

N/AReviewer 2· 95% conf

The paper reports only descriptive statistics (means, percentages) and does not perform any inferential statistical tests, so the dimension is not applicable.

Evidence

direct quote[Results and Discussion, Section 3 and Table 3]

“Each value of tensile properties represents the mean value for three tested samples.”

absence[Entire paper]

No p-values, confidence intervals, or effect sizes are reported anywhere in the paper.

WARNReviewer 3· 80% conf

The study uses descriptive statistics (mean values from three replicates) for tensile strength, hardness, and microstructure percentages, but no inferential statistical tests are reported, and the data presentation lacks error bars and individual data points for tensile/hardness values.

Evidence

direct quote[Results, sections 3.2–3.4]

“Each value of tensile properties represents the mean value for three tested samples.”

absence[Table 3, Figures 6–10]

No standard deviations, error bars, or confidence intervals are reported.

absence[Methods]

Statistical software is not identified.

The paper states 'Data will be made available on request' in the Declarations section. This is reported_but_inadequate by the tiered criteria because no repository, platform, or mechanism beyond a raw request is given. No code was used beyond routine image analysis, so code_sharing is not applicable. No accession numbers are provided.

Sub-criteria

code sharingN/A

accession numbersNOT REPORTED

repository depositNOT REPORTED

data availability statementINADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

A data availability statement is present but vague ('on request'), without a repository or accession number; no code is shared.

Evidence

direct quote[Declarations, Data availability statement]

“Data will be made available on request.”

FAILReviewer 2· 95% conf

The data availability statement is vague ('on request') with no repository or mechanism, and no custom code is shared, resulting in a fail for this dimension.

Evidence

direct quote[Declarations]

“Data will be made available on request.”

WARNReviewer 3· 85% conf

A data availability statement exists but is vague: 'Data will be made available on request' with no repository, accession number, or managed-access platform specified; no code was generated.

Evidence

direct quote[Declarations]

“Data will be made available on request.”

absence[Declarations and paper text]

No repository deposit or accession numbers are provided.

absence[Methods]

No custom code was generated; image analysis program is not named.

The methods section provides enough detail to replicate the casting and testing procedures. No clinical trial is involved, so trial_registration is not applicable. No reporting guideline (e.g., ARRIVE, CONSORT) is referenced. All stated outcomes (pearlite%, nodularity, hardness, tensile strength) are reported in tables/figures. Limitations are not explicitly discussed in a separate section but can be inferred from the discussion (e.g., 'provision of engine cylinder blocks face some difficulties'). Conclusions are proportional to the data (the paper does not overclaim). A funding statement ('This research did not receive any specific grant') and a conflict-of-interest statement ('The authors declare no conflict of interest') are provided.

Sub-criteria

funding coiADEQUATE

trial registrationN/A

reporting guidelineNOT REPORTED

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedINADEQUATE

conclusions proportionalADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

The paper reports methods adequately for replication (chemical compositions, casting parameters, testing standards), but lacks a reporting guideline, trial registration (n/a), and does not discuss limitations or funding sources (funding declared as none).

Evidence

direct quote[Methods, Sections 2.1–2.3]

“Tensile test samples were produced according to standard ASTM E8M; these samples were taken from step bloc as shown in .”

absence[Conclusions and Discussion]

No limitations discussion is provided.

direct quote[Declarations, Funding statement]

“This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.”

PASSReviewer 2· 85% conf

The methods are described in sufficient detail, all outcomes are reported, and funding/conflicts are disclosed, but the limitations discussion is minimal.

Evidence

direct quote[Methods, Section 2]

“Tensile test samples were produced according to standard ASTM E8M; these samples were taken from step bloc as shown in . For each thickness, three repetition tensile specimens were machined for testing.”

direct quote[Results and Discussion, Section 3.1]

“Actually, the chemical composition that can be used to synthesis of vermicular graphite cast iron in one foundry may be not suitable for another foundry.”

WARNReviewer 3· 85% conf

Methods are described in sufficient detail for replication, a reporting guideline or trial registration is not applicable, all outcomes appear reported, and limitations are implicitly addressed but not in a dedicated section. Conclusions are proportional, and a funding/COI statement is provided.

Evidence

paraphrase[Methods, sections 2.1–2.3]

“The experimental procedure describes induction furnace parameters, chemical compositions, ladle treatment, sample preparation, etching, microscopy, and tensile testing per ASTM E8M.”

absence[Entire paper]

No reporting guideline is referenced.

direct quote[Declarations]

“This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.”

30 copyedit issues flagged (6 major): mostly typo, grammar, clarity.

Checked 19 references: 0 verified — 19 not checked.

Αlpha¹ Rigor Action ItemsFinal pass before journal submission

This is a post-publication audit. The paper is generally sound but has notable reporting gaps: the absence of any measure of variability (SD, error bars) on the reported mean values, the lack of a clear data repository, and the omission of a limitations section weaken its reproduction value. An informed reader should interpret the numerical results (e.g., tensile strengths of 716 vs. 748 MPa) as point estimates without quantitative uncertainty. An erratum adding standard deviations for the reported means and a corrected data availability statement would strengthen the manuscript's credibility.

1.
HIGHstatistics
In the Results and Methods, add standard deviations (SD) or standard errors (SEM) for all reported mean values (tensile strength, hardness, pearlite%, nodularity%) and define what the error bars in figures represent.
Reporting means without any measure of variability makes it impossible for readers to assess the precision or reproducibility of the measurements.
2.
HIGHdata code
Replace the vague data availability statement ('Data will be made available on request') with a specific repository (e.g., Zenodo, Figshare, Mendeley Data) and include a DOI for the raw data (e.g., individual tensile curves, micrographs).
A non-specific 'on request' statement does not ensure long-term access and is considered inadequate by most journals.
3.
HIGHreporting
Add a dedicated Limitations section (after the Conclusions) discussing the lack of inferential statistics, the small number of replicates per condition (n=3), the single casting run per condition, and the generalizability of the results to other foundries.
Explicitly addressing limitations improves scientific transparency and helps readers interpret the findings appropriately.
4.
MEDIUMother
In the Methods, provide the vendor name and catalog numbers for the alloying additives (ferrotitanium, tin, copper) and the etching agent (Nital), or state that they were sourced from standard industrial suppliers.
Reproducibility requires that other researchers can obtain identical or equivalent materials.
5.
MEDIUMother
In Methods, Section 2.2, name the image analysis software by product name and version (e.g., 'ImageJ 1.53t', 'AxioVision 4.8') and state the vendor.
Without naming the software, readers cannot ascertain how micrograph measurements (e.g., pearlite%, nodularity) were obtained, affecting reproducibility.
6.
MEDIUMreporting
Add a brief statement that the study followed standard metallographic procedures (ASTM E3 for sample preparation) and tensile testing (ASTM E8M), as a form of reporting guideline compliance.
Referencing applicable standards adds to the paper's transparency and shows adherence to accepted methodologies.
7.
MEDIUMother
Pre-specify inclusion/exclusion criteria for tensile specimens (e.g., 'three tensile specimens were machined per condition; any specimen with visible porosity or surface defects was excluded and replaced') and state explicitly that no outliers were removed or report any exclusions with reasons.
Without pre-specified criteria, there is a risk of selective reporting that reduces the perceived objectivity of the results.
8.
MEDIUMother
Add a statement about whether independent replication was performed (e.g., separate casting runs on different days) or acknowledge that the results are from a single casting run.
Independent replication is essential for establishing the robustness of findings; its absence should be transparently acknowledged.
9.
LOWcopyedit
Revise the author line in the Title to separate the title from the author names, and format author names with proper punctuation (e.g., 'Essam Mahmoud A. Shash, Ahmed Y. Shash*, Hassan Megahed, Emad El-Kashif') with email addresses in footnotes.
The current garbled author line (duplicate emails, missing punctuation) is unprofessional and likely to be flagged by the journal's submission system.
10.
LOWcopyedit
Correct the typo in Methods, Section 2.2: change 'A Zesiss Axiotech' to 'a Zeiss Axiotech' (Zeiss is a well-known manufacturer).
Misspelling a major manufacturer's name is a basic oversight that undermines the paper's polish.
11.
LOWcopyedit
Throughout the manuscript, add the missing article 'is' where needed (e.g., 'Compacted graphite cast iron composed of...' → 'Compacted graphite cast iron is composed of...').
Missing verbs and awkward syntax reduce readability and may distract reviewers.
12.
LOWcopyedit
In the Abstract, Keywords section: remove the duplicate keyword list and the trailing period, and ensure the list is formatted consistently.
Duplication and inconsistent formatting in a prominent metadata field can confuse indexers and readers.

Full text (22,827 chars)Analyzed: Jul 6, 2026

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