The Inconel 625 round bar is a bar made from a nickel-based chromium-molybdenum-niobium alloy that is used in applications where corrosion resistance and strength and reliable performance are paramount in challenging operating environments. The governing material specification for round bars and rods is ASTM B446, with a corresponding ASME specification ABME SB446.

Kalpataru Piping Solutions supplies Inconel 625 round bars in various forms and sizes to serve various industrial purposes. This guide aims to explain Inconel 625 – its chemical composition, mechanical properties, (UNS N06625), its constituents, state, sizes available, how to calculate the weights of Inconel 625 and its applications so as to provide accurate information for engineers, consumers, and purchasing department for their understanding of the specification prior to making an order. 

What Is an Inconel 625 Round Bar?

Inconel 625 is a nickel-based chromium-molybdenum-niobium alloy represented by UNS N06625. Its European material number is 2.4856. The alloy is characterized by the combination of nickel and chromium, together with the considerable amounts of molybdenum and niobium, which bestows it with a high resistance to various corrosive environments, in addition to good properties.

Round bar means a solid circular section manufactured in straight lengths. According to ASTM B446 the alloy UNS N06625 comes in several different heat-treated forms. The chosen condition defines both strength and ductility of the alloy and its intended application.

The larger range of Inconel Round Bar range might help a customer in selecting proper grades when comparing Inconel 600, Inconel 625 and Inconel 718.

Inconel 625 Chemical Composition

The exact chemical composition should always be checked against the material test certificate supplied for the actual heat. ASTM B446 specifies chemical requirements for UNS N06625 and also covers dimensional and mechanical requirements for the applicable product condition.

Inconel 625 Mechanical Properties

These indicators illustrate the requirement that the condition is essential in the purchase specification. Buyers ordering Inconel 625 Round Bar should indicate the required ASTM B446 grade and ask for the EN 10204 3.1 material test certificate in situations where traceability is needed.

Standard Specifications and Equivalent Grades

ASTM B166 has been widely misapplied when discussing Inconel 625 bars. The standard actually applies to nickel-chromium-iron alloys, including Inconel 600. The correct standard when specifying Inconel 625 bars and rods is ASTM B446 and if an ASME standard is required, ASME SB446 should be referenced. 

Inconel 625 Equivalent Grades

Equivalent designations help when comparing international material specifications, but they should not be treated as automatic permission to substitute one specification for another. Project specifications, design codes and purchaser requirements should be checked before making a substitution.

Approximate Weight Reference

The theoretical weight of a solid round bar can be estimated using its diameter and material density. Inconel 625 has a density of approximately 8.44 g/cm³.

Actual supplied weight can vary because of dimensional tolerance, length tolerance and finishing operations. Buyers requiring exact shipment weight should use the dimensions and certified material details for the supplied bar

Inconel 625 Industrial Applications 

• Oil and Gas: Used for components exposed to aggressive fluids, elevated temperatures and chloride containing offshore environments.
• Marine and Shipbuilding: Suitable for selected components exposed to seawater and chloride environments where corrosion resistance is important.
• Aerospace: Used for exhaust components, ducting and other parts requiring strength and corrosion resistance. Aerospace projects may specify AMS 5666. SeeInconel 718 Round Bar for another nickel alloy option.
• Chemical Processing: Suitable for equipment exposed to acids, chlorides and other corrosive media.
• Nuclear and Power Generation: Used for selected components requiring corrosion resistance and mechanical performance under demanding service conditions.
• Pulp and Paper: Used in equipment exposed to corrosive and elevated temperature conditions. SeeInconel Round Bars in the Pulp and Paper Industry

How to Select the Right Inconel 625 Round Bar

Selecting an Inconel 625 round bar should consider the service environment, applicable standard and material condition. Evaluate temperature, pressure and corrosion exposure before selecting ASTM B446 or ASME SB446. Choose the required annealed, solution annealed or cold worked condition based on mechanical requirements. Then specify diameter, length, tolerance and surface finish. Finally, define inspection requirements such as chemical analysis, tensile testing, hardness testing, dimensional inspection and an EN 10204 3.1 MTC. This approach helps ensure the selected bar meets the application, dimensional and documentation requirements.

Frequently Asked Questions

Aluminium perforated sheets are flat sheets of aluminium with a specific arrangement of holes. The holes can be geometric shapes such as circular, square, rectangular, and hexagonal, or can be customized according to the needs of the users. The combination of aluminium and regulated perforation makes these sheets useful for construction, ventilation, machine protection, screening, ceiling, shading, and other practical purposes.

Kalpataru Piping Solutions was founded in 2015 and is a certified ISO 9001:2015 manufacturer, producer, distributor, and exporter of metal products. The company offers its clients a wide array of piping products, both metallic and non-metallic, for various industrial and engineering applications.

This article aims to inform readers about the types, sizes, thicknesses, and functionalities of aluminium perforated sheets. It also explains the meaning of terms such as perforation size and pitch and their impact on the area of a particular project.

What Is Aluminium Perforated Sheet?

Aluminium perforated sheet is a flat aluminium sheet containing a regular arrangement of holes or openings. The openings are created by punching, stamping, or controlled cutting according to a specified hole shape, size and spacing.

Round holes are widely used for general ventilation, screening, and architectural applications. Square, slotted, hexagonal and decorative patterns can be selected when the project requires a different airflow characteristic, appearance or screening effect.

The manufacturing process also affects the final specification. Mechanical punching is commonly used for standard patterns and production quantities, while CNC or laser cutting can be considered for special shapes, decorative designs and customised layouts.

A perforated aluminium sheet is normally specified using the aluminium grade, temper where required, thickness, hole shape, hole diameter, pitch, pattern arrangement, open area, sheet dimensions and surface finish.

Sizing and Standard Dimensions

The available size of an aluminium perforated sheet depends on the base sheet, perforation pattern, thickness, production equipment and project requirement. Common sheet dimensions used in the market include both metric and imperial formats.

For buyers who need general aluminium sheet information, Kalpataru also provides information onAluminium Plates and Sheets. The present guide focuses specifically on perforated aluminium sheet selection.

Types of Aluminium Perforated Sheet

Aluminium perforated sheet is available in different patterns based on the shape and arrangement of the openings. The selected pattern depends on open area, airflow, visibility, appearance and application requirements.

Aluminium Perforated Sheet Thickness and Classification

Thickness is one of the most important factors when selecting aluminium perforated sheet. A thinner sheet can reduce weight and may be suitable for decorative applications, while a thicker sheet can provide greater rigidity for equipment covers, industrial screens and fabricated panels.

A useful general classification is shown below.

These categories are general selection guidelines rather than universal industry classifications. The actual thickness should be selected according to the required load, span, support arrangement, fabrication method, hole pattern and application.

Understanding Open Area Percentage

Open area percentage is the proportion of the total aluminium perforated sheet surface occupied by holes. It is mainly determined by the hole size, pitch and perforation pattern. A higher open area generally allows greater airflow and light transmission, while a lower open area leaves more metal between the openings and can provide greater screening or privacy.

As a general selection guide:

These ranges are general guidelines rather than universal classifications. The required open area should be selected according to airflow, visibility, light transmission, acoustic requirements, structural considerations and the specified hole pattern.

Common Aluminium Grades Used for Perforated Sheet

Common grades considered for aluminium sheet applications include 1100, 3003, 5052 and 6061.

The exact grade and temper should be confirmed against the applicable material specification and project requirements.

Chemical Composition of Common Aluminium Grades

For Aluminium 1100, silicon and iron are commonly controlled together with a combined maximum limit of 0.95% rather than being treated as two independent maximum values. 

Mechanical Properties of Common Aluminium Grades

Manufacturing Process and Surface Finishes

Aluminium perforated sheet is produced using mechanical punching, stamping, CNC or laser cutting. Mechanical punching suits standard patterns and higher production volumes, while CNC or laser cutting supports decorative, complex and customised designs. The selected process depends on hole geometry, sheet thickness, quantity and dimensional accuracy.

Common finishes include mill, anodized, powder coated and painted finishes. Anodizing improves surface durability and appearance, while powder coating provides colour options and additional surface protection. The finish should be selected based on the installation environment, appearance requirements and fabrication process.

Does Aluminium Perforated Sheet Have a Working Pressure Rating?

Aluminium perforated sheet should not automatically be treated as a pressure rated component.

The presence of holes changes the effective section of the material and the structural behaviour of the panel. A pressure-containing application therefore requires a separate engineering assessment based on the material, thickness, perforation pattern, dimensions, support arrangement, temperature, and design pressure.

For pressure containing equipment, the applicable equipment design code and project specification should take precedence over a general perforated sheet specification.

Standards, Inspection, and Material Documentation 

Aluminum perforated sheets are normally defined in regard to their standards, the standards referring to compositions, mechanical features and the dimensions of the aluminum. ASTM B209 determines aluminum and aluminum alloy sheet and plate while EN 485 contains specifications regarding aluminum and aluminum alloy sheets, strips and plates. EN 573 provides the definition of the chemical composition and designation of wrought aluminum and aluminum alloys while JIS H4000 treats aluminum and alloyed aluminum sheets, plates and strips used for industrial purposes.

A typical material verification process may include:

How to Select the Right Aluminium Perforated Sheet

Selecting the right aluminium perforated sheet starts with defining the application. First, identify whether it is required for ventilation, screening, privacy, decoration, filtration, acoustic treatment or equipment protection. Next, determine the required open area for airflow, visibility and light transmission. Choose the hole pattern based on functional and visual requirements. Select the aluminium grade according to the service environment and corrosion exposure. Finally, specify the sheet thickness, dimensions, hole diameter, pitch, pattern arrangement, surface finish and fixing method. This ensures the sheet is selected for performance rather than appearance alone.

Frequently Asked Questions

The most important thing about Inconel from a specs point of view is its ability to maintain strength and resist oxidation at high enough temperatures that would otherwise cause other stainless steels to become soft or scale. one heat limit. Grade 625 tops out well below grade 601. The chart below lines up the maximum service temperature for every Inconel and Incoloy grade Kalpataru Piping supplies, so you can shortlist a grade for a spec or RFQ in one pass. For the fuller picture on composition, general properties, and melting point, start with our Inconel material grades, properties, and composition guide, then come back here for the temperature-specific comparison.

Inconel Maximum Service Temperature: All Grades (Master Chart)

Strength Retention vs Temperature (Inconel 600 and 625)

A max temperature figure only tells you when a grade starts to fail. It does not tell you how much strength you still have at 400°C versus 700°C, which is the number that actually drives a wall-thickness or fastener-torque calculation. The table below tracks tensile and yield strength across five temperature points for Inconel 600, and flags where the same data needs to be pulled for Inconel 625.

Frequently Asked Questions

Duplex 2205 and Super Duplex 2507 are on the same spec sheet for pressure vessels, offshore piping, seawater systems, and the choice between them really comes down to one question: how much chloride exposure.The duplex workhorse is 2205, the one sold and priced for use in moderate-chloride and general industrial applications. The 2507 is more expensive, but provides real headroom where seawater, subsea, and high pressure are involved where there is no room for pit or crevice failure. The tables below provide you with the composition, PREN, mechanical, standards and welding data you need. The Duplex stainless steel 2205 to 2507 comparison is the most direct of our comparison posts, but if you aren’t already familiar with what duplex stainless steel is and how the grade family is divided, take the time to read our guide to duplex stainless steel first.

What Is Duplex 2205?

Duplex stainless steel commonly utilized in industry includes the Duplex 2205 (UNS S32205/S31803), which consists of almost equal amounts of ferrite and austenite. That mixed structure gives it close to double the yield strength of the common 300-series austenitic stainless steels It is the most preferred steel until it is surpassed by the operational environment due to its easy availability and low cost. Duplex 2205 is available in various forms from Kalpataru Piping.

What Is Super Duplex 2507?

Super Duplex 2507 (UNS S32750), on the other hand, uses the same two-phase metallurgy but goes one step ahead with alloying elements – higher amounts of chromium, molybdenum, and nitrogen when compared with the 2205 alloy, resulting in improved resistance to pitting and crevice corrosion in environments having high chloride content, and an increased strength. This increased margin comes at a higher cost, and it is also not easy to weld and machine. Therefore, the Super Duplex 2507 is used only where there is really tough service requirement and not just as a general replacement to 2205.

Chemical Composition: Duplex 2205 vs Super Duplex 2507

The difference starts with alloy content. 2507 carries meaningfully more chromium, molybdenum, and nitrogen than 2205, and that gap is what drives every other difference on this page.

PREN and Corrosion Resistance of Duplex 2205 vs Super Duplex 2507

Mechanical Properties of Duplex 2205 vs Super Duplex 2507

Both grades outperform standard austenitic stainless steel on strength, a direct result of the duplex microstructure. 2507’s higher alloy content pushes that advantage further, at some cost to ductility.

Standards Cross-Reference Duplex 2205 vs Super Duplex 2507

Duplex 2205 vs Super Duplex 2507: Welding and Fabrication

Applications: Where Each Grade Is Actually Used

Duplex 2205 applications

• Chemical processing equipment and pressure vessels
• Heat exchangers in moderate-chloride service
• Onshore oil and gas piping and process lines
• Desalination plant components outside the most aggressive zones
• Marine and coastal structural components

Super Duplex 2507 applications

• Offshore oil and gas platforms, topside and subsea
• Subsea pipelines and flowlines
• High-pressure seawater injection and cooling systems
• Desalination plants in the highest-chloride, highest-temperature zones
•  Heat exchangers in continuous seawater service

How to Choose Between Duplex 2205 and Super Duplex 2507

• Chloride exposure: moderate exposure, splash zones, or general industrial chemical service points to 2205; continuous seawater immersion, subsea, or high-chloride process streams point to 2507.
• Pressure and wall thickness: if 2507’s higher yield strength lets you drop a wall-thickness schedule while still meeting the pressure rating, the weight and material savings can offset a meaningful part of its price premium.
• Cost and lifecycle cost: 2205 is the more economical choice up front and the wider-availability grade. 2507 costs more per kilogram but can cost less over the service life of the asset when the alternative is early pitting failure and unplanned downtime.
• What to put in the purchase order: specify a minimum PREN value rather than a brand name, name the required filler metal and any PWHT, and ask for a mill test certificate with heat traceability on any critical order, since 2205 and 2507 are not visually distinguishable from finish alone.

Frequently Asked Questions

Inconel 625 and Stainless Steel 316 both show up on the same spec sheets for oil & gas, chemical processing and marine equipment, but one is a nickel-based superalloy and the other is an iron-based stainless, and mixing them up on a BOM gets expensive fast.The niobium is about 4 times the molybdenum and 4 times the nickel. What makes Inconel 625 more corrosion resistant and stronger than SS 316 is not a “premium” version of 316, but rather a different type of material (a nickel-based superalloy versus an iron-based stainless steel) and the difference in composition that translates into the additional corrosion margin, strength and high temp resistance. The question is, whether that margin is worth the price is strictly dependent on what the part actually has to live on. It covers the tested composition of both materials (per ASTM B443/B444/B446 for Inconel 625 and per ASTM A240/A312/A276 for SS 316), how they change between each other, this may be obvious to some, but it bears repeating how a spec sheet applies when it’s directly linked to a real part, whether that’s a round bar, pipe or tube, or tube fitting.

What Is Inconel 625?

Inconel 625 is a nickel-chromium-molybdenum superalloy, registered under UNS N06625, with a deliberate niobium (columbium) addition that sets it apart from ordinary nickel-chromium alloys. The niobium provides solid-solution strengthening without requiring heat treatment and just as importantly it stabilizes the alloy against sensitization (carbide precipitation) during welding and elevated-temperature service, which is a failure mode SS 316 remains exposed to unless the low-carbon 316L variant is specified. The alloy is covered by three ASTM standards depending on product form: B443 for plate/sheet/strip, B444 for seamless and welded pipe, and B446 for rod and bar  all sharing the same UNS N06625 composition. There are also two structural grades: Grade 1 (annealed, suited to structural use up to roughly 593°C) and Grade 2 (solution-annealed for superior high-temperature creep resistance). Aashish Metal & Alloys stocks Inconel 625 as round bars, pipes and tubes, and tube fittings, alongside the full Inconel product range.

What Is SS 316?

SS 316 is an austenitic chromium-nickel-molybdenum stainless steel, registered under UNS S31600, and one of the most widely specified stainless grades in industrial use. The molybdenum addition  2 to 3%  is what separates it from SS 304 and gives it meaningfully better resistance to chloride-driven pitting and crevice corrosion. SS 316 is covered by ASTM A240 (plate/sheet/strip), A312 (pipe), and A276 (bar), all under UNS S31600. Like Inconel 625, it has variants worth knowing: 316L, the low-carbon version used wherever the part will be welded, and 316Ti, the titanium-stabilized version used for resistance to sensitization in the 550–800°C range. Aashish Metal & Alloys carries SS 316 as pipes and tubes, tube fittings, fasteners, and shims, across the broader stainless steel product range.

Inconel 625 vs SS 316: Chemical Composition Table

Composition data for this comparison varies depending on where you look, and at least one widely cited supplier table gets a key figure wrong  it lists Inconel 625’s iron content as “Balance,” which isn’t correct. Iron is the base element in stainless steel, which is why SS 316’s iron content correctly reads as a balance figure. But in Inconel 625, nickel is the base element, and iron is a controlled minor addition capped at 5% maximum per ASTM B443/B444/B446. The table below is sourced to the governing ASTM standards for both materials:

Key Differences Between Inconel 625 and SS 316

1. Corrosion Resistance

Both alloys resist chloride-driven pitting and crevice corrosion because both carry molybdenum in their passive surface layer. Where Inconel 625 pulls ahead is the niobium addition, which stabilizes the alloy against sensitization during welding and high-temperature exposure, a vulnerability SS 316 doesn’t fully escape unless the low-carbon 316L variant is specified. That combination of higher molybdenum content plus niobium stabilization is also why Inconel 625 holds up in more aggressive acid environments sulfuric, phosphoric, hydrochloric and under stress-corrosion cracking conditions where SS 316 will eventually degrade.

In milder environments general chemical exposure, food processing, moderate marine atmospheres the two perform comparably, which is exactly why SS 316 remains the economical default and Inconel 625 gets reserved for genuinely aggressive service.

2. Mechanical Strength

Worth comparing against standard minimums rather than a flat “higher/lower” claim, since actual mill-certified figures typically run above the specified floor for both materials:

3. High-Temperature Performance

This is the sub-topic where sources tend to blur two different limits together, so it’s worth separating them clearly. SS 316 has good oxidation resistance in intermittent service up to 870°C and in continuous service up to 925°C  but continuous use in the 425–860°C range specifically isn’t recommended where subsequent aqueous corrosion resistance matters, because that band promotes carbide precipitation (sensitization) unless the 316L or 316Ti variant is used. That sensitization caution band is a different thing from the oxidation-resistance ceiling, and conflating the two produces a misleadingly low “limit” for SS 316.

Inconel 625 doesn’t carry that same mid-range caution band. It holds strength and corrosion resistance up to roughly 980°C, which is the real reason it gets specified for continuous elevated-temperature service that would put SS 316 into its sensitization-risk zone.

4. Weldability & Fabrication

Both alloys weld well, but not identically. Inconel 625 requires ERNiCrMo-3 filler metal and tighter heat-input control to avoid Laves-phase segregation in the weld zone, and it work-hardens faster during machining, which raises tooling wear and machining cost. SS 316 welds with standard austenitic technique and readily available 316L filler, and machines conventionally without the same work-hardening penalty.

5. Cost & Machinability

Inconel 625 costs several multiples of SS 316 per kilogram, driven by its far higher nickel and molybdenum content plus the niobium alloying addition  all of which track global commodity metal pricing rather than sitting at a fixed premium. That’s also why this guide won’t quote a specific price multiple: nickel- and molybdenum-linked pricing moves with the market, and a hard number here would be stale within months. For a deeper look at how alloy cost tracks nickel and molybdenum pricing, request a quote directly. 

Which One Should You Choose?

Frequently Asked Questions

When selecting piping, tubing, or marine hardware in extreme conditions, marine engineers and buyers are faced with one vital dilemma, which is Copper Nickel 90/10 or 70/30? Both alloys are high-grade copper-nickel (Cu-Ni) alloys known for their resistance to corrosion in saltwater, biofouling and stress corrosion. An incorrect selection can result in failure early due to erosion-corrosion at high velocities or unnecessary engineering due to the use of too much nickel. There is a comparison between UNS C70600 (90/10) and UNS C71500 (70/30) below, to aid in the procurement decision.

What Is Copper Nickel 90/10 (UNS C70600)?

Copper Nickel 90/10 (UNS C70600, EN CW352H, BS CN102) is a copper alloy with approximately 10% Ni and controlled amounts of Fe, and Mn. Iron is added (usually 1.0%–1.8%) to create a coating of iron oxide, which provides a protective layer on the surface of the alloy when it comes in contact with seawater; this layer is self-healing. This protective film offers outstanding protection from general corrosion, pitting and stress corrosion cracking. The high thermal conductivity, natural resistance to marine biofouling (e.g. barnacles and mussels) and its relatively low cost make C70600 the most commonly specified Cu-Ni alloy for commercial marine piping, seawater desalination and heat exchanger tubing.

What Is Copper Nickel 70/30 (UNS C71500)?

Copper Nickel 70/30 is a material made of approximately 70% copper and 30% nickel, with small amounts of iron and manganese. The significantly greater nickel content changes the mechanical characteristics of C71500 to provide improved tensile strength, fatigue resistance and ability to withstand impingement attack and erosion-corrosion from high velocity turbulent fluids. It has a high level of resistance to general corrosion in marine environments, but the higher nickel content results in higher cost and a slightly less ability to resist biofouling attachment than 90/10. C71500 is widely used in high pressure seawater heat exchangers and offshore oil platforms where no operating failures are tolerable, as well as in naval surface ships and submarine piping systems.

Chemical Composition Comparison Between Copper Nickel 90/10 vs 70/30

Copper Nickel 90/10 vs 70/30 Mechanical Properties Comparison 

Thermal & Electrical Conductivity of Copper Nickel 90/10 vs 70/30

Weldability, Fabrication & Galvanic Compatibility

CuNi 90/10 (UNS C70600) and CuNi 70/30 (UNS C71500) are very weldable using the GTAW/TIG, GMAW/MIG and SMAW processes. Qualified welding procedure and the applicable material specification should be used to interpret the type of filler metal to be used, and the welding of specific Cu-Ni joints should be performed with Ni-Cu type filler metal (ERNiCu-7). For common piping applications, both alloys can typically be welded without any preheating or PWHT; however, this may be different for certain thicknesses, joint designs, service conditions, and codes. If the two grades are electrically coupled in sea water, a galvanic potential difference may be created which may be in favor of the CuNi 90/10 as more anodic. Factors such as dielectric isolation, exposed-area ratios, and wall-thickness allowances are important points to consider when dealing with galvanic interaction, which can be evaluated by engineers.

Cost Comparison: Nickel Pricing & TCO

Because the higher nickel content exposes CuNi 70/30 to changes in the raw-material prices of nickel and copper, in general, CuNi 70/30 is more expensive than CuNi 90/10. It is important to note that a specific premium over LME nickel and copper prices may not be taken for granted, as the actual price difference will depend on various factors such as product form, dimensions, quantity, supplier and market conditions. UNS C70600 is generally less expensive than the other, but for applications where the higher nickel content of UNS C71500 allows it to meet more stringent service demands in seawater, the advantages of such a change may not justify the extra expense. Initial CAPEX and potential maintenance, replacement and downtime costs over the expected service life should therefore be taken into consideration when selecting the appropriate grade.

Applications Uses of Copper Nickel 90/10 vs 70/30

Frequently Asked Questions