FAQ

INTRODUCTION TO CHROMX

1. What does MMFX® mean?

MMFX® stands for Martensitic Microcomposite Formable Steel. In its formation, the company adopted this name to
pay homage to the material science technology on which it was based. All MMFX steels include a martensitic phase
combined with other steel phases, such as austenite, that give MMFX steels its advantageous properties.

2. What does ChrōmX® stand for?

The product brand name, ChrōmX®, combines the alloying element, ferrochrome or chrome, with the “X” adopted as a symbol for steel, as in the name “MMFX.” ChrōmX steels are produced through a combination of steel alloys and controlled manufacturing processes. While only one element of the process, ferrochrome plays an important role in the production of ChrōmX steels.

3. What is the history of MMFX?

MMFX Steel Corporation, a privately held company based in Irvine, California, was founded in June 1998 to commercialize its unique micro- and nano steel technologies that create superior products by manipulating material’s microstructures. MMFX’s initial production of ChrōmX steel reinforcing bar was in 2001 and it has been selling its high strength, corrosion resistant steel in the market since 2002.

4. How long have the MMFX products been on the market?

MMFX’s initial production of ChrōmX steel reinforcing bar was in 2001 and it has been selling its high-strength, corrosion-resistant steel in the market since 2002.

5. Is ChrōmX’s nanotechnology patented?

ChrōmX’s nanotechnology is protected by six (6) U.S. patents and related filings in approximately 50 countries/regions. Importantly, the patents cover both the manufacturing process and the unique microstructure of the steel.

6. Is ChrōmX steel proprietary?

ChrōmX steels are proprietary, but are sold under a general non-proprietary specification. To support the use of innovation by state and federal departments, the FHWA issued a memorandum titled, Guidance on Patented and Proprietary Product Approvals dated November 30, 2011. This release introduces revised guidance on the application of 23 CFR 635.411 Material or product selections. The regulation generally prohibits the use of federal funds in payment of any premium or royalty on any proprietary material, specification, or process specifically set forth in the plans or specifications for a project; however, the regulation and revised FHWA Guidance layout several exemptions allowing the use of proprietary products, which include competitive bidding or certification that no equally suitable alternative exists.

There is no other product on the market today offering the high strength with ductility and uncoated corrosion resistant properties of ChrōmX, along with the benefits derived from these properties; therefore, the state transportation department can certify that there is no equally suitable alternative. Otherwise, if the state believes that suitable equals exist, the state can include ChrōmX in their specifications along with those suitable equals.
It is important to also note that MMFX Steel Corporation has an open supply chain including multiple manufacturers, distributors and fabricators, in support of distribution and competition with respect to its’ innovative products.
(Reference Memo re: Federal Highway Administration’s (FHWA) Guidance on use of patented and proprietary products, November 2012)

7. What are the MMFX’s product lines?

MMFX applies its nanotechnology to produce and sell high strength concrete reinforcing products named ‘ChrōmX’ with varying levels of corrosion resistance, so that owners, developers and structural engineers can design using high strength efficiencies, while selecting the product that best fits the service life expectation for the given structure. ChrōmX is categorized as follows:

  • ChrōmX 9000 Series. This high corrosion resistant steel comes in 100 (690) and 120 (830) grades and provides over 100 years of service life in concrete.
  • ChrōmX 4000 Series. This mid-corrosion resistant steel also comes in 100 (690) and 120 (830) grades and provides approximately 40 – 60 years of service life in concrete, depending on the specific application and design.
  • ChrōmX 2000 Series. This product offers the high strength properties of 100 KSI (690 MPa) and 120 KSI (830 MPa) yield strength for applications where corrosion is less of a concern.

ChrōmX steels are made in the following products:

  • Straight and coiled deformed bars
  • Smooth rounds
  • Dowel bars
  • Wire rod
  • Flats
  • Williams Form Engineering product line: threaded bar, soil nails, tie-backs & tie-downs, micro-piles, rock anchors, guy anchors, wind turbine foundation bolts and marine bulkhead wall tie-rods
  • Couplers (made of ChrōmX by Barsplice, Erico, Detra, Williams Form and HRC)
  • Additional products, such as wire and strand, are in development.

PRODUCTION AND DISTRIBUTION

8. How is ChrōmX produced and where?

ChrōmX is produced through a combination of alloy additions and controlled manufacturing process. The combination of the steel’s chemical composition and production process develops the unique microstructure of the steel that drives the advantageous product properties.
In North America, ChrōmX steel bars are manufactured by Cascade Steel Rolling Mills, Inc. in McMinnville, Oregon. Cascade is a MMFX supplier, as well as a licensee for the western part of North America.

9. Is ChrōmX produced on the east coast of North America?

An east coast producer has not been established yet, but MMFX has a network of distributors that inventory and help service eastern North America. MMFX is seeking the right partner mill to produce ChrōmX on the east coast.

10. What about Canada, Asia or Africa?

Currently, the material is produced at:

  • McMinnville, Oregon for North America;
  • Dubai, UAE for the Middle East North African region; and
  • Talcahuano, Chile for South America

MMFX is actively seeking and in discussions with several additional production facilities globally.

11. What is MMFX’s annual production?

MMFX partners with multiple production mills around the world. Production is scalable with the expansion of our production partners capacity.

12. How often does Cascade Steel Rolling Mills produce ChromX?

Cascade produces ChrōmX about every 30 days to fill product to order and replenish inventory.

13. Who is the largest consumer of ChrōmX?

MMFX does not publish its customer list, but there are numerous specifications that drive the sale of ChrōmX into states’ bridge works, marine concrete works and large commercial construction projects. VDOT’s and Alberta’s CRR policies are significant recognitions of the benefits of ChrōmX for the infrastructure market. Our customer list is expanding with the increased use in other states, and in the growth of the commercial high rise market.

14. Who are MMFX’s major distributors and where are they located?

MMFX five main distributors in the United States are:

  • Adelphia Metals, LLC with locations in Minnesota, Illinois, Indiana, Pennsylvania, New Jersey and Georgia;
  • Cascade Steel Rolling Mills with locations in Oregon and California;
  • Harris Supply Solutions, Inc. with locations in Washington, California, Colorado, Montana, Utah, Nevada, Arizona, New Mexico, North Dakota, Missouri, Nebraska, Oklahoma, Texas, Illinois, Ohio, Alabama and South Carolina;
  • Metal Partners with locations in Pennsylvania, Maryland, Virginia, Illinois, Minnesota, Iowa, Missouri, Texas, Colorado, New Mexico, Arizona, Nevada, and California.
  • Rockingham Steel / Transcon Supply with multiple facilities in Virginia
  • SteelCon Supply with locations in West Virginia and Florida;
  • Stuart Building Materials with multiple locations in Southern Florida; and
  • Williams Form Engineering with locations in Washington, California, Oregon, Colorado, Michigan, Pennsylvania, Georgia, British Columbia and Ontario.

The contact information for each of our distributors is located on MMFX’s website http://www.mmfx.com/products/to-order/

15. How long will it take to supply and deliver ChrōmX to a jobsite? What is the lead time?

MMFX maintains a sizable inventory either at the production mill or at distributor locations. In addition MMFX’s mill partner, Cascade Steel, produces steel about every 30 days to fill orders and replenish inventories. Lead time for steel that is not in inventory, such as special order, should take no more than 45 – 60 days.

16. What sizes and lengths does ChrōmX rebar come in? Can I get special lengths? What is the minimum quantity for special lengths?

ChrōmX steel reinforcing bar standard lengths are 40 and 60 feet for #4 through #11, #14 and #18, and 40 feet for #3 straight bar sizes. #3 and #4 rebar are also available in coil. Custom mill-cut lengths are available by special order, minimum 20 feet and up to 72 feet (80 feet maximum for #11, #14 and #18), of 50 tons or greater increments.
(Reference ChrōmX Product Overview for more information)

17. Does ChrōmX weigh the same as standard rebar?

Yes. ChrōmX weighs the same for similar lengths and diameters.

SPECIFICATION AND ENGINEERING

18. Is ChrōmX produced under ASTM and AASHTO Specifications?

ChrōmX 9000, 4000 and 2000 series are produced in full accordance to ASTM International – ASTM A1035 (2015), Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement, Grades 100 & 120 types CS, CM and CL, respectively. ChrōmX series meet and exceed ASTM A615-15 Grade 100.
ChrōmX 9000 series are produced in full accordance to AASHTO MP 18 M/MP 18 (2014) Standard Specification for Uncoated, Corrosion-Resistant, Deformed and Plain Alloy, Billet-Steel Bars for Concrete Reinforcement and Dowels Grade 100.

19. What is the alloy content of ChrōmX?

ChrōmX series are low-carbon, chromium alloy steel bars. ChrōmX 9100 and 9120 (formerly MMFX2), 4100 and 4120, and 2100 and 2120 rebar shall meet the requirements of Table 1 as per ASTM A1035-15.
Table 1– Maximum Chemical Constituents (Weight %)Alloy Type Carbon Chromium Manganese Nitrogen Phosphorus Sulfur Silicontable-FAQ-web(A)AASHTO MP 18 M/MP 18 has a minimum 9.2% Cr content.

20. How do engineers specify ChrōmX?

ChrōmX 9000, 4000 and 2000 products can be specified as reinforcing bars conforming to ASTM A1035-15 CS, CM, CL, respectively, along with the grade designation (100 or 120). For highways and bridges applications, according to AASHTO, ChrōmX 9100 products can be specified as low chromium reinforcing bars conforming to AASHTO MP18 along with the grade designation (100).

21. What types of applications should engineers consider using ChrōmX steel reinforcing bars?

ChrōmX 9000 and 4000 series rebar are ideal for reinforcing concrete structural members and systems exposed to, or in direct contact with, corrosive conditions. Whether ChrōmX 9000 or 4000 is used in these corrosive environments depends on the target service life for the project. ChrōmX 9000 has been successfully used in bridge decks and beams, foundation piles and systems, pavement dowel and tie bars, diaphragm walls, marine structures and seawalls, industrial equipment foundations and exposed balconies since 2002.
The high strength properties of ChrōmX 9000, 4000 and 2000 series steel bars allow for more efficient and cost-effective designs and construction, improved constructability by easing congestion and shortened construction schedules. High strength applications include: building mat foundations and shear walls, parking garages, bridge superstructures, and hydroelectric dams.

22. What types of projects were built with ChrōmX?

Since 2002, ChrōmX has been used in various public infrastructure and public/private development projects in the United States, Canada, Mexico, Puerto Rico, Bahamas and the Middle East. It has been used in bridges (abutments, columns, girders and decks), floating decks, Navy piers, high rise mat foundations and shear walls, pavement dowels, precast pilings and substructures.

23. How do engineers design with ChrōmX Grade 100? Are there guidelines designer can refer to?

Engineers shall comply with applicable building codes by cities, counties and states, ACI 318 and IBC 2009 and 2012. In addition, designers shall be guided by the ACI-ITG6 and ICC ESR-2107, which provide design guidelines on the use of ASTM A1035 up to 100 ksi yield in structural designs. The AASHTO LRFD Bridge Design Specifications also provides guidance for designing bridges up to 100 ksi yield strength.
Additionally, MMFX offers design guidance and assistance to engineers when they are faced with unique structural challenges. High strength, innovative solutions that mitigate construction challenges that improve constructability with cost competitive, jointly developed solutions are provided.

24. Can engineers design with ChrōmX in accordance to the International Building Codes (IBC)?

ICC ESR-2107 provides design guidelines on the use of ASTM A1035 up to 100 ksi yield in structural designs in accordance to the Acceptance Criteria ICC AC429, thereby conforming to the requirements of IBC 2009 and 2012.

25. Can engineers design with ChrōmX in accordance to the American Concrete Institute (ACI)?

In 2010, the ACI has published the ITG-6R-10, Design Guide for the Use of ASTM A1035/A1035M Grade 100 Steel Bars for Structural Concrete, which guides engineers to safely design of ASTM A1035/A1035M at a yield strength of 100 ksi.

26. Can engineers design with ChrōmX in accordance to the Canadian Standards Association (CSA)?

Currently, there are no Canadian specifications and standards that cover the MMFX’s products or their use in concrete design. The numerous projects that MMFX has done in Canada have been constructed to ACI, ICC-ES or AASHTO design standards or standards specific to agencies in a province. However, MMFX is currently working with the CSA to incorporate ChrōmX products into the CSA specifications of approved material and 100 ksi design specifications. It is expected that the approval process will be completed in 2016.

27. Does AASHTO allow the usage of ChrōmX? What strength does AASHTO allow?

Yes, the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications, 7th Edition 2014, allows the use of steel reinforcing bar up to 100 KSI (690 MPa). Therefore all ChrōmX series that are certified in accordance to ASTM A1035/A1035M and/or AASHTO MP18 are allowable.

28. What DOT’s have accepted the usage of ChrōmX?

DOTs that have realized the benefits by designing and/or constructing with ChrōmX in bridge decks, other structural members, and/or using pavement dowel include: Alabama, Arizona, California, Colorado, Connecticut, Delaware, Florida, Idaho, Indiana, Iowa, Kentucky, Massachusetts, Maine, Michigan, New Hampshire, New Mexico, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Utah, Vermont, Virginia, Washington and Wisconsin.
Canadian MOTs of British Columbia, Alberta, Manitoba, and New Brunswick have also used ChrōmX.

29. What parts of a bridge can ChrōmX be used in?

ChrōmX 9000, 4000 and 2000 series can be used for reinforcing all bridge members. ChrōmX has been used in bridge abutments, columns, caps, girders, decks (top and bottom mats), curbs, and parapets since its inception.
AASHTO LRFD Bridge Design Specifications, 7th Edition 2014, allows the use of ChrōmX up to 100 KSI (690 MPa).

30. Does ChrōmX perform well in the presence of Chlorides and Deicing Salt?

Yes. ChrōmX 9000 products (formerly MMFX2) are 5 times more corrosion resistant than carbon steel rebar. Their chloride threshold, the level of chloride concentration at which corrosion initiates, is 4 times higher and their corrosion rate is one-third the rate of conventional rebar. The combination of ChrōmX 9000’s higher chloride threshold and slower corrosion rate provides a 100-year service life in concrete. Extending the operational service life – the time from construction to first repair – significantly lowers life-cycle costs, especially important for bridges, marine piles and severe soil applications.
Similarly, ChrōmX 4000 products have a chloride threshold of twice that of conventional rebar and again a much slower corrosion rate. ChrōmX 4000 can provide a service life in concrete of 40 to 60 years, depending on the specific application and design.

31. Is there test data available to prove ChrōmX 9000 products will last 100 years?

Numerous independent third party testing studies, such as universities and state DOTs, have found ChrōmX 9000 products (formerly MMFX2) provide a service life of over 100 years.
(Reference Material Properties and Design Considerations for listing of tests and studies)

32. How does ChrōmX compare with epoxy coated rebar (ECR) for corrosion-resistance?

ChrōmX 9000 products significantly outperform ECR for corrosion resistance. Many field studies show that ECR adds little to no corrosion protection or additional service life due to the damage and failure of the epoxy coating in the field. ECR is estimated to provide roughly 30 years of service life, while the ChrōmX 9000 series provides over 100 years; and the ChrōmX 4000 series provides 40 to 60 years, depending on the specific application and design.
Further, the ChrōmX products are simpler to handle in the field. Because ChrōmX relies on its unique microstructure for its corrosion resistance and not a fragile coating, it does not have special handling requirements like galvanized, epoxy-coated or stainless steel bars. ChrōmX rebar can be handled just like conventional carbon steel bars.
(Reference Specialty & Corrosion-Resistant Steel Reinforcement: Product Guide for Handling and Storage by Concrete Reinforcing Steel Institute)

33. How does ChrōmX compare with galvanized for corrosion-resistance?

ChrōmX 9000 products outperform galvanized rebar for corrosion resistance. Many field studies show that galvanizing rebar adds only a few years to the service life, far below the 100 years provided by ChrōmX 9000 series (formerly MMFX2). One such study, Critical Chloride Corrosion Threshold for Galvanized Reinforcing Bars, David Darwin, et. al., The University of Kansas Center for Research, Inc. (Dec. 2007), measured the chloride threshold of ChrōmX 9000 at 2.5 times higher than galvanized rebar.
ChrōmX 4000 products are currently estimated to provide comparable corrosion resistant performance to galvanized bars. The University of Kansas study referenced above found that galvanize rebar has a chloride threshold of 1.6 times that of conventional steel. Comparably, the chloride threshold of ChrōmX 4000 has been measured at 2 times that of conventional steel, resulting in a ChrōmX 4000’s chloride threshold that is more than 1.2 times higher than that of galvanized steel.
Further, the ChrōmX products are simpler to handle in the field. Because ChrōmX relies on its unique microstructure for its corrosion resistance and not a fragile coating, it does not have special handling requirements like galvanized, epoxy-coated or stainless steel bars. ChrōmX rebar can be handled just like conventional carbon steel bars.
(Reference Specialty & Corrosion-Resistant Steel Reinforcement: Product Guide for Handling and Storage by Concrete Reinforcing Steel Institute)

34. How does ChrōmX compare with stainless steel (SS) rebar?

ChrōmX 9000 series are the most comparable MMFX products to SS rebar. ChrōmX 9000 and SS rebar are the only products that provide over 100-year service life in concrete, yet ChrōmX 9100 and 9120 are one-third to one-half the cost of SS rebar, depending on the SS grade selected. ChrōmX 9000 products have been designated the most cost effective solution for corrosion by the Virginia Transportation Research Council (VTRC).
Further, ChrōmX rebar can be handled just like conventional steel bars, without the special handling requirements associated with SS bars. For example, ChrōmX is not considered dissimilar to carbon steel for galvanic corrosion purposes. Therefore, ChrōmX does not need to be isolated from carbon steels in construction, as SS bars do.
(Reference Specialty & Corrosion-Resistant Steel Reinforcement: Product Guide for Handling and Storage by Concrete Reinforcing Steel Institute and MMFX Engineering Bulletin #5 Dissimilar Metals Considerations)

35. What is the cost comparison between ChrōmX 9100 and corrosion resistant products on the market?

Bar for bar in place cost estimates, ChrōmX 9100 rebar is approximately one-half the cost of stainless steel rebar. It is roughly 30% more than galvanized and 50% more than ECR bar for bar; however, the additional handling and field costs of galvanized and ECR need to be taken into account. Further, ChrōmX 9100 outperforms both galvanized and ECR for corrosion resistance resulting in the lowest life cycle cost over the competing products. In fact, upon the first repair of structures built with galvanized rebar or ECR the costs are estimated at 5 times or more than if constructed with ChrōmX 9100 rebar.
ChrōmX 9100 is a high-strength rebar. Therefore the high strength efficiencies offered by ChrōmX’s 100 KSI yield strength can lower upfront costs that more than offset the bar for bar premium cost, resulting in significant net construction cost savings. Example calculations are available based on specific project assumptions and factors.

36. What is the cost comparison between ChrōmX 4100 and epoxy or galvanized rebar?

Based on bar for bar in-place cost estimates, ChrōmX 4100 rebar is comparable in cost to galvanized and/or epoxy-coated rebar (ECR). However, the additional handling and field costs of galvanized and ECR need to be taken into account. Further, ChrōmX 4100 outperforms both galvanized and ECR for corrosion resistance resulting in the lowest life cycle cost over the competing products.
ChrōmX 4100 is a high strength steel rebar. Therefore the high strength efficiencies offered by ChrōmX’s 100 ksi yield strength can lower upfront costs that more than offset the bar for bar premium cost, resulting in significant net construction cost savings. Example calculations are available based on specific project assumptions and factors.

37. What is the cost comparison between ChrōmX 2100 and conventional black bar?

ChrōmX 2100 has a high strength cost premium over conventional Grade 60 and Grade 75 rebar; however, the high strength efficiencies offered by ChrōmX’s 100 ksi yield strength more than offset the bar for bar premium, resulting in significant net construction cost savings. Example calculations are available based on specific project assumptions and factors.
ChrōmX 2100 is competitively priced against ASTM A615 Grade 100 rebar, and also offers better and more consistent mechanical properties, such as a tensile-to-yield (T/Y) ratio over 1.25.

38. What is the Yield Strength?

A yield strength or yield point of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible.

39. What is the Ultimate Tensile Strength?

Ultimate tensile strength, often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. The ultimate tensile strength is usually found by performing a tensile test and recording the engineering stress versus strain. It is the highest point of the stress-strain curve.

40. What is the Modulus of Elasticity?

Young’s modulus, sometimes called the modulus of elasticity, also known as the tensile modulus or elastic modulus, is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the stress along an axis over the strain along that axis in the range of stress in which Hooke’s law holds.
ChrōmX has a Modulus of Elasticity (E) of 29 x 106 psi.

41. What is the development length of steel reinforcing bar?

Developing the proper lap length of concrete-embedded rebar is crucial for obtaining the rebar’s full tensile capacity. If the overlap distance is less than the defined development length (i.e. the minimum lap length required), the bar will pull out of the concrete. According to ACI 318, the development length is based on the attainable average bond stress over the length of embedment of the reinforcement. The development length is a function of the steel bar yield stress, the concrete compressive strength, the distance between the bar and the edge of the concrete (“clear cover”), and the bar diameter.

42. How to determine the developing length of ChrōmX rebar?

The process for determining the development length of ChrōmX ASTM A1035/A1035M CS, CM and CL Grade 100 rebar is consistent with conventional reinforcing steel grades with slight changes to the applicable equations. In 2010, the American Concrete Institute (ACI) published the ITG-6R-10 Design Guide for the Use of ASTM A1035/A1035M Grade 100 Steel Bars for Structural Concrete, which guides engineers to safely design structures using ASTM A1035/A1035M up to a yield strength of 100 ksi. The ACI ITG-6R-10 slightly modified the equations in ACI 408R-03 Bond and Development of Straight Reinforcing Bars in Tension for both confined and unconfined ASTM A1035/A1035M Grade 100 rebar.
(Reference MMFX Engineering Bulletin #8 Rebar Splicing Solutions)

43. Does ChrōmX have similar bond strength as conventional rebar?

ChrōmX steel bars have similar concrete bond strength as compared to conventional rebar. It provides better bond strength than coated corrosion-resistant rebar such as epoxy-coated and galvanized. For example, to develop the proper lap length of concrete-embedded epoxy-coated rebar, a 20% additional embedment in length is required compared to ChrōmX rebar in similar applications to provide similar bond strength.

44. If builders have a rebar congestion issue, can ChrōmX help?

Yes. One of the major benefits of the ChrōmX products is the high strength properties and the potential to help reduce rebar congestion. Using Grade 100 reinforcing steel can reduce rebar requirements from 20 – 40% over grade 60 reinforcing steel.

45. Are high strength couplers available for mechanically splicing ChrōmX?

High-strength mechanical splices and anchorages are available from multiple coupler manufacturers. Additionally, couplers made from MMFX materials can also be purchased from these coupler manufacturers.
(Reference MMFX’s Engineering Bulletin #8 Rebar Splicing Solutions)

46. Can ChrōmX be used in seismic zones?

The use of ChrōmX rebar in seismic zones 3 and 4 and SDC D, E and F is limited to transverse reinforcement for concrete confinement with fyt up to 100 ksi for special moment frames and special structural walls as permitted by Section 21.1.5.4 of ACI 318-08; however, in foundation mats where seismic movement isn’t an issue, ChrōmX rebar can be used for longitudinal and transverse concrete reinforcement. A number of studies are underway to expand the applications of ChrōmX products in high seismic zones.
(Reference Design Guide for Use of ASTM A1035 in Concrete Bridge Elements with Consideration to Seismic Performance by Henry G. Russell, et. al. and S. K. Ghosh)

47. Is ChrōmX more brittle due to their high-strength?

ChrōmX steel bars have the same minimum ductility as conventional steel bars and superior ductility compared to other high strength products due to the MMFX microstructure. There is no compromise between strength and ductility. Each heat and each size produced from that heat receives a bend test per ASTM and the results are recorded on the certified material test report (mill certificate).

48. Can MMFX’s products exceed the bend requirements of ASTM A615? Can they be field bent? Is heat bending permitted?

Engineers shall follow the ACI-ITG6 Sec 10.4 on bending which refers to ACI 318-08 Sec 7.2 on minimum bending diameter requirements. The same applies to conventional black steel. ChrōmX rebar can be field bent per ACI 318, which prohibits heat bending and bending bars embedded in concrete. Designers shall follow the ACI-ITG6 Sec 10.4 on bending which refers to ACI318-08 Sec 7.2 on rebar bending requirements.
Heat bending is prohibited, because heat can adversely impacts the high strength and the high corrosion resistant properties of ChrōmX steel reinforcing bars.

49. Can ChrōmX be welded? Do you have a welding protocol?

ACI-ITG6 Sec 10.4 restricts welding, but it also refers designers to ASTM A1035 Note 2 that states welding should be approached with caution. MMFX is working on the development of a welding protocol.

50. Can ChrōmX be threaded?

Yes. ChrōmX can be rolled and cut threaded.
(Reference Williams Form Uncoated Corrosion Resistant Steel Bar product brochure)

51. Is ChrōmX referenced in the US Army Corps of Engineers Guide Specifications?

Yes. ASTM A1035 is referenced in USACE Unified Facilities Guide Specifications, Division 03 – Concrete, Section 03 20 00.00 10, Concrete Reinforcing.

FABRICATION AND INSTALLATION

52. Does MMFX fabricate steel rebar?

MMFX does not fabricate steel rebar, but rather sells its products to fabricators.

53. Is it easy to fabricate ChrōmX? Is there a special procedure for handling?

ChrōmX steel rebar can be fabricated and handled just like conventional steel rebar. Standard fabrication equipment can be used. There are no special handling requirements in contrast to epoxy-coated, galvanized, stainless steel or even Z-Bar steel bars.
(Reference Specialty & Corrosion-Resistant Steel Reinforcement: Product Guide for Handling and Storage by CRSI)

54. How does ChrōmX look when it arrives at the fabricator?

Similar to conventional steel: as rolled, bundled and tagged.

55. Does ChrōmX have standard mill marks to distinguish from standard black bar?

Yes. To distinguish ChrōmX rebar from other steel rebar, it is marked with the following series of letters and numbers. Figures 1, 2 and 3 illustrate the markings on ASTM A1035-15 Types CS, CM and CL steel reinforcing bars respectively.

Bar identifier “CRX” for ChrōmX:
1. Product designation “9”, “4” and “2” for ChrōmX 9000, 4000 and 2000, respectively;
2. Point of origin – letter or symbol established as the manufacturer’s mill designation (e.g. “C” for Cascade Steel);
3. Size designation – number corresponding to ASTM inch-pound bar designation number (e.g. “5” for #5 bar) or metric measurement (e.g. “16” for 16 mm bar);
4. Type of steel – letters indicating that the bar was produced to ASTM A1035 and AASHTO MP 18 specification (e.g. “CS”, “CM” and “CL” for ChrōmX 9000, 4000 and 2000, respectively); and
5. Minimum Yield / Grade Designation number corresponding to bar minimum yield strength / strength grade (e.g. “100” for 100 KSI or “690” for 690 MPa yield strengths).

Figure 1 ASTM A1035 – CS Markings

ChromX9100-English-Designation-web

Figure 2 ASTM A1035 – CM Markings

ChromX4100-English-Designation-web

Figure 3 ASTM A1035 – CL Markings

ChromX2100-English-Designation-web

56. Will ChrōmX rust?

ChrōmX steel rebar will rust; however, the high chloride threshold and slow corrosion rates prolong the life of the rebar and the concrete structure reinforced by it, providing extended service-life in concrete.
Mill scale on the surface of the bar will rust with shallow pitting if exposed to the environment, but the rusting of the mill scale should not result in deep pitting or severe corrosion of the bar deformations. Mill scale oxidation generally has no effect on the performance of the rebar and is not considered a cause for rejection under ASTM, AASHTO, ACI or CRSI standards.
(Reference MMFX Engineering Bulletin #6 Guidelines for Handling ChrōmX Steel Reinforcing Bar Oxidized Mill Scale and CSRI Technical Note: Field Guide for Rust on Reinforcing Bars)

57. Why is there rust on the rebar delivered? Is it acceptable?

ChrōmX bars are delivered “as rolled” from the mill and contain “mill scale” on the surface of the bars. The mill scale can rust when exposed to water, air moisture or other corrosive elements resulting surface rust on the bar. Mill scale oxidation generally has no effect on the performance of the rebar and is not considered a cause for rejection under ASTM, AASHTO, ACI or CRSI standards.
(Reference MMFX Engineering Bulletin #6 Guidelines for Handling ChrōmX Steel Reinforcing Bar Oxidized Mill Scale and CSRI Technical Note: Field Guide for Rust on Reinforcing Bars)

58. Can ChrōmX rebar be cut in the field? Is there a protocol or a procedure?

ChrōmX rebar can be cut in the field using conventional equipment, but torch cutting is prohibited, because heat adversely impacts the high strength and the high corrosion resistant properties of ChrōmX steel reinforcing bars.

59. Can ChrōmX be used in contact or close proximity to other materials?

Several studies have reported that there is no added risk of combining conventional steel products, such as rebar, couplers, wires, etc., to MMFX’s products in concrete. There is therefore no dissimilar metals issue and no need to isolate MMFX’s products from conventional steels.
(Reference MMFX Engineering Bulletin #5 Dissimilar Metal Considerations)