Call Us Today: +86-731-89903933|info@shunfusteel.com
FacebookLinkedInYouTubePinterestTiktok

AISI 4145H MOD Steel

Home/Alloy Steel, Product/AISI 4145H MOD Steel
AISI 4145H MOD Steel2026-04-29T01:53:41+00:00

Project Description

AISI 4145H Modified Steel

AISI 4145H Modified is a premium chromium-molybdenum alloy steel engineered for exceptional yield strength, toughness, and fatigue resistance in high-stress environments. As a dedicated manufacturer for the oil, gas, and mining sectors, Hunan ShunFu Metal Material Co., Ltd. produces this grade to withstand the most demanding downhole conditions. Backed by our API Q1 certification and extensive experience exporting to over 50 countries, we are a trusted supply partner to the world's top 10 oilfield service companies. Our in-house metallurgical controls and precision processing ensure every bar meets the rigorous demands of critical drilling operations.

AISI 4145H Modified steel round bars for oilfield drill collar manufacturing
AISI 4145H Modified steel bars (ShunFu Metal)

Equivalent Grades

  • US / API: AISI 4145H Modified
  • UNS: G41450 (Modified)
  • Europe (EN): 42CrMo4 (Base equivalent, modified)

Applications

AISI 4145H Modified is the preferred material for high-stress drilling components. ShunFu Metal supplies this grade tailored to the exact manufacturing stages of our clients in the Oil & Gas, Mining, and Drilling engineering sectors:

  • Drill Collars & Heavyweight Drill Pipe: Supplied by ShunFu Metal as precision BTA-bored hollow bars, fully quenched and tempered to guarantee uniform through-thickness hardness.
  • Tool Joints & Subs: Delivered as forged solid round bars, utilizing our high-ratio forging presses to achieve optimal grain flow before delivery.
  • Stabilizers & Reamers: Provided as custom forged blanks, heat-treated in our API-calibrated furnaces to ensure superior wear resistance against abrasive wellbore conditions.
  • Downhole Motor Components: Supplied as precision-machined solid bars, undergoing 100% ultrasonic testing by our quality team to ensure zero internal defects for directional drilling assemblies.

Specifications & Standards

ShunFu Metal manufactures AISI 4145H Modified steel in strict compliance with the following international standards:

  • API Spec 7-1: Specification for Drill Stem Elements
  • NS-1 & DS-1: Enhanced material specifications for premium drilling components
  • ASTM A322: Standard Specification for Steel Bars, Alloy, Standard Grades
  • ASTM A370: Standard Test Methods and Definitions for Mechanical Testing of Steel Products
  • ISO 9001: Quality Management Systems

ShunFu Metal strictly organizes production according to the above standards and can issue corresponding material test certificates based on specific customer requirements.

Available Sizes & Delivery

ShunFu Metal offers AISI 4145H Modified in highly flexible dimensions to suit diverse manufacturing needs. We supply hot-rolled and forged solid round bars (OD 2″ to 12″), as well as precision-bored hollow bars. Our heavy forging capabilities ensure a high forging ratio for superior grain structure, while our API-calibrated heat treatment furnaces and advanced machining center—equipped with BTA deep hole drilling, CNC lathes, and long-distance gunhole drilling—deliver exact tolerances.

Delivery & MOQ:

  • Ready Stock: Common sizes available for immediate shipment, minimum order of 1 piece, delivery in ~7 days.
  • Custom Forgings/Rolled Bars: Standard MOQ from 3 tons, delivery in ~30 days.
  • Small Batch Special Melts: Utilizing our small induction furnaces, we can melt custom heats starting at 3–5 tons.
  • Large Volume Orders: Processed rapidly through our 30–60 ton Electric Arc Furnaces for fast turnaround.

Chemical Composition

ShunFu Metal verifies the chemical composition of every single heat through in-house spectrometry prior to pouring, ensuring all elemental ranges strictly comply with API and customer specifications. We can also fine-tune the chemistry to meet your specific mechanical performance targets.

Chemical composition of AISI 4145H Modified (weight %)
OD Range C Si Mn P (Max) S (Max) Cr Mo Ni (Max) Cu (Max)
Up to 10″ (254mm) 0.43-0.48 0.20-0.35 0.75-1.10 0.025 0.025 0.95-1.20 0.15-0.35 0.25 0.35
Over 10″ (254mm) 0.43-0.48 0.20-0.35 0.75-1.10 0.025 0.025 0.95-1.30 0.15-0.35 0.50 0.35

Melting & Processing

ShunFu Metal offers flexible melting routes: standard EAF + LF + VD for excellent cleanliness, ESR or PESR for enhanced structural uniformity, and VIM + VAR for the most critical requirements. Customers can consult our metallurgical team to select the optimal melting process for their specific application.

Mechanical Properties

ShunFu Metal provides comprehensive mechanical property test reports issued by our accredited laboratory prior to delivery, with all data fully traceable to the specific heat and production batch.

Mechanical properties of AISI 4145H Modified
OD Range Tensile Strength (Min-Max) Yield Strength 0.2% (Min-Max) Elongation (Min) Reduction of Area (Min) Impact (Min Avg at +20°C) Hardness
Up to 7″ (178mm) 140 - 165 ksi 120 - 140 ksi 14% 45% 32 ft-lbs (44 J) 285 - 340 HB
7″ to 10″ (178-254mm) 130 - 160 ksi 115 - 135 ksi 14% 45% 32 ft-lbs (44 J) 285 - 340 HB
Over 10″ (254mm) 125 - 155 ksi 105 - 125 ksi 14% 45% 32 ft-lbs (44 J) 285 - 340 HB

Heat Treatment

Heat treatment parameters for AISI 4145H Modified
Process Temperature Range Cooling Method Objective
Quenching 840°C – 870°C Liquid Quench (Polymer/Oil) Achieve uniform martensitic structure throughout the cross-section.
Tempering 540°C – 680°C Air Cool Relieve internal stresses and achieve the target 285-340 HB hardness range.

ShunFu Metal’s heat treatment furnaces are strictly maintained and regularly calibrated in accordance with API standards. This ensures absolute temperature uniformity and process repeatability, providing reliable and consistent mechanical properties for every batch of AISI 4145H Modified steel we produce.

Surface Finish & Machining

Leveraging our comprehensive in-house machining facility, ShunFu Metal delivers AISI 4145H Modified products in various surface conditions. We offer rough turning, precision grinding, and CNC milling to achieve tight dimensional tolerances and specific surface roughness (Ra) values. For hollow drilling components, our specialized BTA deep hole boring and roller burnishing equipment produce flawless internal finishes. We also provide shot peening to enhance fatigue resistance. By keeping these precision machining processes in-house, we guarantee strict quality control and offer a true factory-direct advantage for complex component geometries.

Quality Assurance & Inspection

ShunFu Metal implements rigorous quality control at every production stage. Our inspection protocol includes 100% ultrasonic testing per ASTM A388, chemical analysis, mechanical testing, and precise dimensional checks. We perform four-quadrant hardness testing and detailed metallographic examinations to verify uniform through-hardening and grain structure. As an API Q1 and ISO 9001 certified manufacturer, we guarantee that every piece of AISI 4145H Modified steel meets stringent oilfield safety standards. We provide EN 10204 3.1 certification standard (3.2 available upon request) and seamlessly accommodate third-party inspections from agencies like SGS or TÜV.

Packing & Shipping

With extensive experience exporting to over 50 countries, ShunFu Metal ensures secure transit. Black surface bars are tightly bundled with steel wire, while precision-machined products receive multi-layer protective wrapping. All materials are coated with premium anti-rust oil to prevent corrosion during ocean freight. We fully accommodate destination-specific packaging and documentation requirements.

Frequently Asked Questions

Can ShunFu Metal supply AISI 4145H Modified to API Spec 7-1, NS-1, and DS-1 specifications?

Yes. Our production and testing protocols are fully aligned with API Spec 7-1. For the enhanced requirements of NS-1 and DS-1, our laboratory conducts the necessary extended impact and mid-radius mechanical testing to certify full compliance before shipment.

What is the minimum order quantity for this drill collar steel?

We maintain a ready stock of common sizes for immediate delivery with a 1-piece MOQ. For custom forged sizes or specific chemistry modifications, our flexible melting capabilities allow us to process orders starting at just 3 to 5 tons.

Do you provide pre-machining services for drill components?

Absolutely. ShunFu Metal operates an advanced machining center equipped with BTA boring machines, long-distance gunhole drilling, and CNC lathes. We can supply fully bored hollow bars, rough-turned forgings, or semi-finished drill collar blanks, significantly reducing your final machining time and costs.

What is the typical delivery time for AISI 4145H Modified bars?

Common sizes held in stock ship in approximately 7 days. Custom forged or rolled bar orders have a standard lead time of around 30 days, depending on quantity and finishing requirements.

ShunFu Metal Co., Ltd. is one of the largest high quality oilfields product manufacturers in China, and its products cover various oilfields such as gas pipe, oil casing, tubing, anti-corrosion line pipe, corrosion resistance alloy pipe, etc. …
Company Info

Contact Info

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners. View more
Cookies settings
Accept
Privacy & Cookie policy
Privacy & Cookies policy
Cookies list
Cookie name Active

Privacy Policy

What information do we collect?

We collect information from you when you register on our site or place an order. When ordering or registering on our site, as appropriate, you may be asked to enter your: name, e-mail address or mailing address.

What do we use your information for?

Any of the information we collect from you may be used in one of the following ways: To personalize your experience (your information helps us to better respond to your individual needs) To improve our website (we continually strive to improve our website offerings based on the information and feedback we receive from you) To improve customer service (your information helps us to more effectively respond to your customer service requests and support needs) To process transactions Your information, whether public or private, will not be sold, exchanged, transferred, or given to any other company for any reason whatsoever, without your consent, other than for the express purpose of delivering the purchased product or service requested. To administer a contest, promotion, survey or other site feature To send periodic emails The email address you provide for order processing, will only be used to send you information and updates pertaining to your order.

How do we protect your information?

We implement a variety of security measures to maintain the safety of your personal information when you place an order or enter, submit, or access your personal information. We offer the use of a secure server. All supplied sensitive/credit information is transmitted via Secure Socket Layer (SSL) technology and then encrypted into our Payment gateway providers database only to be accessible by those authorized with special access rights to such systems, and are required to?keep the information confidential. After a transaction, your private information (credit cards, social security numbers, financials, etc.) will not be kept on file for more than 60 days.

Do we use cookies?

Yes (Cookies are small files that a site or its service provider transfers to your computers hard drive through your Web browser (if you allow) that enables the sites or service providers systems to recognize your browser and capture and remember certain information We use cookies to help us remember and process the items in your shopping cart, understand and save your preferences for future visits, keep track of advertisements and compile aggregate data about site traffic and site interaction so that we can offer better site experiences and tools in the future. We may contract with third-party service providers to assist us in better understanding our site visitors. These service providers are not permitted to use the information collected on our behalf except to help us conduct and improve our business. If you prefer, you can choose to have your computer warn you each time a cookie is being sent, or you can choose to turn off all cookies via your browser settings. Like most websites, if you turn your cookies off, some of our services may not function properly. However, you can still place orders by contacting customer service. Google Analytics We use Google Analytics on our sites for anonymous reporting of site usage and for advertising on the site. If you would like to opt-out of Google Analytics monitoring your behaviour on our sites please use this link (https://tools.google.com/dlpage/gaoptout/)

Do we disclose any information to outside parties?

We do not sell, trade, or otherwise transfer to outside parties your personally identifiable information. This does not include trusted third parties who assist us in operating our website, conducting our business, or servicing you, so long as those parties agree to keep this information confidential. We may also release your information when we believe release is appropriate to comply with the law, enforce our site policies, or protect ours or others rights, property, or safety. However, non-personally identifiable visitor information may be provided to other parties for marketing, advertising, or other uses.

Registration

The minimum information we need to register you is your name, email address and a password. We will ask you more questions for different services, including sales promotions. Unless we say otherwise, you have to answer all the registration questions. We may also ask some other, voluntary questions during registration for certain services (for example, professional networks) so we can gain a clearer understanding of who you are. This also allows us to personalise services for you. To assist us in our marketing, in addition to the data that you provide to us if you register, we may also obtain data from trusted third parties to help us understand what you might be interested in. This ‘profiling’ information is produced from a variety of sources, including publicly available data (such as the electoral roll) or from sources such as surveys and polls where you have given your permission for your data to be shared. You can choose not to have such data shared with the Guardian from these sources by logging into your account and changing the settings in the privacy section. After you have registered, and with your permission, we may send you emails we think may interest you. Newsletters may be personalised based on what you have been reading on theguardian.com. At any time you can decide not to receive these emails and will be able to ‘unsubscribe’. Logging in using social networking credentials If you log-in to our sites using a Facebook log-in, you are granting permission to Facebook to share your user details with us. This will include your name, email address, date of birth and location which will then be used to form a Guardian identity. You can also use your picture from Facebook as part of your profile. This will also allow us and Facebook to share your, networks, user ID and any other information you choose to share according to your Facebook account settings. If you remove the Guardian app from your Facebook settings, we will no longer have access to this information. If you log-in to our sites using a Google log-in, you grant permission to Google to share your user details with us. This will include your name, email address, date of birth, sex and location which we will then use to form a Guardian identity. You may use your picture from Google as part of your profile. This also allows us to share your networks, user ID and any other information you choose to share according to your Google account settings. If you remove the Guardian from your Google settings, we will no longer have access to this information. If you log-in to our sites using a twitter log-in, we receive your avatar (the small picture that appears next to your tweets) and twitter username.

Children’s Online Privacy Protection Act Compliance

We are in compliance with the requirements of COPPA (Childrens Online Privacy Protection Act), we do not collect any information from anyone under 13 years of age. Our website, products and services are all directed to people who are at least 13 years old or older.

Updating your personal information

We offer a ‘My details’ page (also known as Dashboard), where you can update your personal information at any time, and change your marketing preferences. You can get to this page from most pages on the site – simply click on the ‘My details’ link at the top of the screen when you are signed in.

Online Privacy Policy Only

This online privacy policy applies only to information collected through our website and not to information collected offline.

Your Consent

By using our site, you consent to our privacy policy.

Changes to our Privacy Policy

If we decide to change our privacy policy, we will post those changes on this page.
Save settings
Cookies settings
Go to Top