OEM Manufacturer Cutters/ Knife / Blade Tooling for Cutting

• Customization: Available
• Certification: ISO9001:2008, ISO9001:2000, RoHS, CE
• Application: Cutter Machinery
• Model NO.: bhtie-225
• Standard: Non-Standard
• Coating: Uncoated
• Material: High Speed Steel
• Hardness: HRC45~65
• Thickness Tolerance: +- 0.001
• Flatness: 0.003
• Surface Roundness: Ra 0.1um
• Transport Package: Wooden Case /Pallet
• Specification: custom-made
• Trademark: BHTIE
• Origin: China
• HS Code: 8208900000
• Production Capacity: 390000 PCS Per Month

Product Description

 

 

 

Materials

 

Materials

BHT uses a wide range of high-quality materials to manufacture various industrial blades and machine knives. Materials are as follows: Carbon tool steel (9CrSi, SAE52100, D2, SKD-11, 1.2379), stainless steel (420SS, 440B, 440C), high-chromium tool steel, high speed tool steel (HSS, SKH-51, SKH-9, ASP-23), and tungsten carbide D2 Cold Work Tool Steel D2 features an exceptional dimensional stability, and it is an air hardening, high-carbon, high-chromium (11%) tool steel. It offers an excellent hardness and abrasion resistance, a high hardening rate and an excellent compressive strength. D2 cold work tool steel can be used for cutting tools, shear blades, trimming blades, slitting blades, saw blades, milling tools, woodworking tools, cold working tools, and more. HSS Steel: (1.3343, M2, SKH9, SKH51, SKH2) High speed steel (HSS) is a tool steel known for its high hardness and excellent wear and heat resistance. It has an excellent processability and strength, making it ideal for use in manufacturing complex, thin blades and metal cutting tolls that require a high impact resistance. It is also an excellent choice for high-temperature bearings and cold extrusion dies. This steel type improves mechanical properties and prevents carbide segregation that leads to distortion after heat treatment. Tungsten Carbide Tungsten carbide is a composite material containing hard material with a binder metal. It features an outstanding hardness and is known for its high wear resistance, corrosion resistance and heat resistance. The material will retain its hardness properties, unchanged, even at extreme temperatures of 500 or 1000ºC. Today, tungsten carbide is widely used in manufacturing different cutting tools, including turning tools, milling tools, planing tools, drilling bits, boring tools and much more for processing materials. Materials often include cast iron, non-ferrous metal, plastic, chemical fiber, graphite, glass, stone, ordinary steel, as well as difficult-to-cut materials such as heat resistant steel, stainless steel, high manganese steel and tool steel. We will assist our customers in choosing the right material for their needs. Each of our cutting blades features an optimized, scientific composition, and a moderate amount of rare elements to meet requirements for strength and wear resistance. We have also invested extensively in advanced lab equipment to implement accurate and fast testing, as well as adjustment of the chemical compositions in order to retain the product's required value. We have also developed an HLD series high-alloy material for the fabrication of industrial blades in materials with different thickness levels.

 

 

Processing and Manufacturing

 

Manufacturing	Forging Forging is the process of shaping metal and improving it's microstructure in order to remove loose pieces of metal. Forged parts typically have better mechanical properties than cast parts of the same material. Forging is often an optimum process for manufacturing key parts with a high load and harsh working conditions during mechanical processing. Alloy Sintering Sintering is the process of compacting and forming powder by heating it to a certain temperature (sintering temperature) and maintaining that temperature for a specific period of time. The sintered materials with expected properties are then obtained after the cooling process. Machining While customers appreciate our high-precision machining technique, they quickly get used to it and expect greater accuracy and precision. Facing the evolving customer expectations, BHT constantly raises the bar for machining quality and keeps introducing more advanced semi-automatic or fully automated equipment. These equipment sets, coupled with highly trained senior technicians, ensure a high thickness tolerance of ±0.001mm can be achieved. Smart machining practices also guarantee each cutting blade is manufactured to exact specifications for flatness, parallelism, outer diameter and inner diameter. Surface Treatment After passing though the above processes, the blade would receive surface treatments to get its surface plated with titanium, chromium, or gain a black or blue finish. Properly treated surface is nonstick, rust-proof and helps improve the work life of each slitting blade, thereby saving costs on blade replacement. Final Quality Check Once final touches are added, it marks the end of one manufacturing process. Usually, after the surface treatment, quality check is done to ensure blade quality. This quality inspection process involves the use of vernier caliper, outside micrometer, inside micrometer, micro caliper, Brinell hardness testers, Rockwell hardness tester, surface roughness tester, optical spectrum analyzer, and flaw detector.
Facilities	Production Capacity BHT has gradually emerged as a leader in Chinese cutting blade industry. Our manufacturing facility is among the largest in China, outfitted with top-notch cutter blade and matched mold manufacturing equipment. We've also built separate institutions aiming to design and research new industrial blades and molds which meet customer specific requirements. Please call to get a custom cutter blade tailor made just for you. BHT can custom manufacture cutting blades for your large or small projects. Talents While we do have a product catalogue, we've seldom sold a product exactly as it is listed. Each cutting blade has some aspects customized to fit customer's request and the particular make and model of customer's cutting machine. Experienced customers would spec out which raw material to be used straight away. For other customers, one of our engineers would provide suggestions on raw material selection and walk customers through each stage of industrial blade design and manufacturing processes. Price to Performance Ratio There are many factors that need considering when you purchase industrial blades in batches. In the end, it all comes down to one determinant: cost-performance ratio. That is, whether you can buy a high-quality blade at the lowest possible price. If that is your concern, BHT is the right place! Quality Control More than 200 test instruments ensure product quality. Quality inspectors are constantly trained to strengthen quality control awareness. We strictly adhere to ISO9001 standards under which BHT is certified. Cost Control Raw materials for our slitter blades, press brake tooling and the likes are purchased in batches from our long-term cooperative suppliers, which reduces material procurement cost without budgeting on material quality. Integrated cutting blade production lines deliver improved production efficiency. The inventory level of each product is strictly controlled to reduce costs of carrying excess stocks. BHT's manufacturing facility is one the largest manufacturing plants in China, outfitted with top-notch manufacturing equipment for cutting blades and matched molds. We have also built an independent institution to design and research new industrial blades and molds to better meet changing customer needs. For more information about our customization services, please don't hesitate to reach out to us. Each cutting blade is customized to meet specific customer requests and their specific brand and model cutting machines. Experienced customers can also spec out raw materials they'd like us to use. Other customers can speak with our engineers on which raw materials would work best for the customer's needs in each stage of the industrial blade design and manufacturing process.
Quality Control	BHT uses a variety of advanced measuring and testing equipment to ensure that each industrial blade and machine knife you receive is qualified, such as vernier calipers, micrometers, hardness testers, three-dimensional articulated arm measuring instruments and more.
Packing and Shipping	We only choose the best PVC material to pack up each BHT cutting blade. Then the whole pack would go into a beautiful cardboard box. Top-of-the-line industrial blade, along with an aesthetically appealing package, often makes blade buyers hard to resist. If you are an oversea agent looking to promote sales in your region, BHT blade products would be one of your best bets.
Service and Advantages	We have more than 20 years of experience in processing and customizing industrial blade. We also have a specialist team to provide consulting services for blade manufacturing. Customization services will fulfill customer expectations according to your design, applications, drawings, or written specifications. We provide high quality industrial blades at a competitive price, backed by years of experience in the blade manufacturing field. We use CAD, CAXA, Pro E and other professional software for design, as well as use advanced equipment, including CNC laser cutting machines, CNC lathe machines, CNC drilling machines, CNC grinding machines, vacuum heat treatment furnaces and more in production. You design will be turned into a product that satisfies your requirements within 25 business days. BHT is a specialist cutting blade manufacturer in China. Whatever you need to cut, tissue paper, rubber, plastics, or metal foils, you are sure to find something right here, including the foil slitter blade, tissue cutting blade, plastics cutting blade, press brake tooling, and electrode plate slitter blade. Order Confirmation, Preliminary Price Estimate Once your technical drawings or sample requests are received by our marketing department, we would soon check up on them which spec out the requirements for raw materials, manufacturing processes, and end uses of your desired cutting blades. Based on the price estimates made by our professional engineers, one of BHT oversea sales representatives would convey the accurate price quote, lead time, and shipping information to your. As soon as you confirmed on the order, our business representatives would follow up on your exact requirements presented in the form of technical drawings, samples, pictures, and instructions. If you have trouble providing detailed drawings or product samples, please tell our technical experts who can select the right shape, size, thickness, and bevel angle based on your brief description and intended use of your products. Drawing Confirmation, Production Schedule After we received your product order, our draftsmen would make a technical drawing marked with dimensions and tolerances using CAD, PRO/E and CAXA software. Once you confirmed the drawing, batch production would soon be kick-started. Throughout the entire manufacturing process, there are quality inspectors patrolling around at each stage of the process to ensure processing quality. To ensure on-time delivery, we've specially set up a division called P.M.C Department who keeps track of the production and continuously urges workers on to finish manufacturing in time. When production is completed, quality inspectors at BHT would check the quality of each cutting blade against the requirements specified on the drawing. Qualified products will be imprinted with bar codes using a laser printer and specially treated to resist rust. When all these steps are done, the products are ready to ship out. Cutter Blade Maintenance If any quality problem is found with our cutter blade during use, please call us. It is not uncommon for blades to wear down over time. If the blade gets dull, send it back to us and our men will re-sharpen it.

 

Product Description

 

Packaging knives / blades:

BHT offers a variety of durable and reliable packaging blades and packaging knives for use in the packaging industry. These blades are made of a variety of different materials, including carbon tool steel (9CrSi, SAE52100, D2, SKD-11, 1.2379), high-speed tool steel (HSS, SKH-51,SKH-9, ASP-23) to fabricate these packaging blades, razor sharp packaging knives, punch knives, and other sharp tools. At BHT, we offer custom manufactured packaging blades in different types, including straight, circular and pointed tip shapes with a wide array of cutting edges, such as toothed, serrated, scalloped and many other tooth configurations. This means our blades will meet all of your packaging applications, including fresh and dry food packaging, medical packaging, as well as polyethylene plastic bag manufacturing, film converting, plastic vinyl and foil converting.
Paper Packaging:
honeycomb cardboard, paper sack, paper pouch, kraft paper, industrial-quality paperboard
Plastic Packaging:
Parafilm wrap, heat shrink film, stretch film, POF shrink wrap, CPP, EPP, corrugated plastic sheet
Composite Packaging:
soft package, metallized film, film laminated aluminum film, vacuum metallized paper (coated with aluminum), laminate film, laminate paper, BOPP
Metallic Packaging:
tinplate, aluminum foil, barrel hoop, steel band, wire buckle, aluminum blister pack, PTP aluminum foil, aluminum plate, steel reed
The packaging industry requires a wide range of cutting blades, including the single-bevel circular blade, slitter blade, shear blade, etc. Each BHT cutter blade undergoes advanced heat treatment and is precisely ground to obtain exceptional wear and corrosion resistance.
We offer custom packaging blades and knives services with a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm. We will complete customization within 25 business days after receiving customer provided parameters or design drawings.

Specifications (mm)	Outer Diameterφ (mm)	Inner Diameterφ (mm)	Thickness (mm)
φ180*φ25.4*2	180	25.4	2
φ200*φ25.4*2	200	25.4	2
φ200*φ25.4*2.5	250	25.4	2.5
φ300*φ25.4*3	300	25.4	3
φ350*φ25.4*3	350	25.4	3

Samples

 

Paper Cutting knives / blades:

We will also customize razor sharp paper cutting knives and paper cutting blades according to your requirements within 25 working days. Processing accuracy of these blades is ensured with a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm.

Φ Outer Diameter	Φ Inner Diameter	B Width	Φ Pinhole	Φ Spot-facing	Taper	No.of hole
114	100	40	7	13	90°	3
136	120	50	7	13	90°	3
152	140	50	8.5	16	90°	3
152	140	50	M10			1

 

Specifications	Φ Outer Diameter	Φ Inner Diameter	B Width	α,Blade angle
φ152*φ140*50	152	142	50	30°
φ200*φ180*55	200	180	55	30°
φ200*φ180*50	200	180	55	(single-sided edge)

 

Specifications	α,Clearance angle	α1,Rake angle
φ150*φ90*2*3	35°	5°
φ150*φ90*2*3	60°	5°

 

Specifications	α,Blade angle
φ150*φ90*2*3	45°
φ150*φ90*2*3	60°

 

Food Processing knives / blades:

As an expert manufacturer of food processing blades, BHT has manufactured countless food processing knives and food cutting blades for fresh fruit and vegetable processing, meat and poultry processing, seafood processing, and bakeries.
We use high quality materials in production of these blades, including 4Cr13, 440B, 7Cr17, W6MO5Cr4V2, SKD11 and W18Cr4V, manufacturing blades in a variety of types, including straight, circular, pointed tip, toothed, serrated, scalloped, and perforated shapes.
We also offer custom food processing blades made with a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm. Production is completed in as few as 25 business days.
Samples

Rubber and Tire knives / blades:

BHT specializes in manufacturing and supplying a variety of rubber and tire cutting knives and blades used for slitting, trimming, grinding, pruning and other processing of rubber, synthetic materials, chemical materials, V-belts, tires, and more. No matter what your rubber and tire cutting application is, we have the right rubber cutting blades for your needs, made of a variety of high-speed steel, tungsten steel or alloy steel, 9CrSi, Cr12MoV(SKD-11), W6Mo5Cr4V2(SKH51), and W18Cr4V.
We offer tailored rubber cutting knives and blades in a variety of shapes and sizes, including circular, pointed tip (arrow shape), toothed, serrated, scalloped, perforated, interlocked and many other shapes. Shown below are a few previously produced rubber cutting blades. For more types, or customization services, please provide your design drawings or written specifications, and we will manufacture a high quality, custom rubber cutting blade that meets customer requirements within 25 business days.
Common specifications

Specifications	Φ Outer Diameter	Φ Inner Diameter	No.of gear
φ100*φ20*1	100	20	51
φ100*φ25.4*1	100	25.4	36
φ110*φ60*1	110	60	36
φ100*φ19*1	100	19	72

 

 

Textile Blades and Non-woven Cutting knives / blades:

As a professional manufacturer of quality industrial blades, BHT manufactures and supplies custom textile knives and non-woven cutting blades made from high-speed steel, tungsten steel, alloy steel including 9CrSi, Cr12MoV(SKD-11), W6Mo5Cr4V2(SKH51), W18Cr4V and tungsten carbide. We also customize textile blades and non-woven cutting knives in a variety of shapes, including straight, circular, pointed tip, toothed, serrated, scalloped, perforated, and other shapes.
Shown here are a few previously produced textile knives and non-woven cutting blades. For information about other blade types, or to request a customized blade type, please provide a design drawing or written specifications, and we will manufacture the tailored blade within 25 business days. The processing accuracy of these blades is guaranteed at a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm.

 

Meat and Poultry Processing knives / blades:

At BHT, we are highly specialized in manufacturing poultry processing blades and meat processing knives. With more than 20 years of experience, we provide both standard and custom meat processing blades in a variety of shapes and materials, including carbon tool steel (9CrSi, SAE52100, D2, SKD-11, 1.2379), stainless steel (420SS, 440B, 440C), and high-speed tool steel (HSS, SKH-51,SKH-9, ASP-23).
Shown below are a few previously produced poultry processing blades and meat processing knives, with customization services available upon request. Customization takes 25 business days according to design drawings, specifications or samples.

 

Plastic Cutting knives / blades:

BHT specializes in manufacturing industrial blades and knives, offering standard and customized sharp plastic cutting knives and plastic blades made of a variety of high quality materials, including hardened tool steels and fine grade stainless steels, including 9CrSi, SAE52100, D2, SKD-11, 1.2379, HSS, SKH-51,SKH-9, ASP-23, 420SS, 440B, and 440C.
We offer these blades in a variety of shapes, including straight, circular, pointed tip, toothed, serrated, scalloped and more. The processing accuracy of these blades is ensured with a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm, guaranteeing each blade meets customer expectations with production completed within 25 business days.
Shown below are a few previously produced cutting blades. For other types and customization services, please provide design drawings or written specifications for reference.

Specifications (mm)	Diameter (mm)	Diameter (mm)	(mm)
φ120*φ25.4*2	120	25.4	2
φ150*φ25.4*2	150	25.4	2
φ180*φ25.4*2	180	25.4	2
φ200*φ25.4*2	200	25.4	2
φ250*φ25.4*2	250	25.4	2
φ300*φ25.4*3	300	25.4	3
φ350*φ25.4*3/3.5	350	25.4	3/3.5
φ400*φ25.4*3	400	25.4	3/3.5
φ450*φ25.4*3	450	25.4	3/3.5

Metal Shear Knives, Metalworking knives / blades:

BHT manufactures and supplies standard and custom metal shear knives and metalworking blades for different metal working applications. These knives and blades are custom manufactured in a variety of shapes and sizes, including circular, straight, curved, convex, toothed, serrated, and scalloped. We use only the highest quality steel material in production, including medium & high alloy tool steel, powder metal steel, 9CrSi, Crl2MoV, W6Mo5Cr4V2, WI8Cr4V, as well as nickel-base alloys due to the high temperature resistance.  BHT's metalworking blades are customized with a thickness tolerance of ±0.001mm, surface roughness of Ra0.1μm, and blade bore tolerance of H3. Each of these tests are carried out indoors at a constant temperature.
A few previously made metalworking blades are shown below. For customization information, please don't hesitate to reach out to us.

Leather Cutting knives / blades:

BHT offers both standard and custom leather cutting knives and blades made exclusively from quality tool steel that has been further processed by precision machinery after heat treatment, ensuring the cutting edge features an outstanding sharpness with no deformations, resulting in a smooth cutting kerf.
We manufacture the leather cutting knives and blades in a variety of shapes, including straight, circular, perforated, and toothed.
With more than 20 years of experience, we will customize leather cutting knives and blades according to customer provided design drawings and written specifications. Materials available to choose from include, but are not limited to, 9CrSi, Cr12MoV, W6Mo5Cr4V2, and W18Cr4V. Processing accuracy of these blades can be ensured at a thickness tolerance of ±0.002mm and a surface roughness of Ra0.1μm. Production is completed within 25 business days.
Samples

 

Slitting Machine knives / blades:

BHT offers a variety of standard and custom slitter blades for your specific slitting applications. Our circular slitter knives and rotary slitting blades are widely used for slitting paper, film, gold leaf, varakh, aluminum foil, magnetic tape and other items with minimal cutting resistance and maximum wear resistance. We use high quality materials, including 9CrSi, Crl2MoV, W6Mo5Cr4V2, WI8Cr4V for manufacturing the slitter blades. Each slitter blade is manufactured according to customer requirements for sizes and shapes within 25 business days, with a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm.
Shown below are a few of our previously produced slitter blades. Other types are available upon request.
Top slitter blades

φOuter Diameter	φInner Diameter	B, Width	b, Thickness	C, Key width	H, Key width	α, Blade angle
62	42	2.5	1.5	2.2	44.5	45°
64	40	1.8	1	3	44	45°
75	45	2	1	3	49	45°
75	45	2.5	1.5	3	49	45°
62	42	2	1	2.2	45	45°
100	75	2.3	1	2.2	77.6	45°
105	70	2	1	3.2	75	45°
105	70	2.5	1.5	3.2	75	45°
140	95	2	1	3.2	100	45°

 

Outer Diameter (mm)	Inner Diameter (mm)	B, Width (mm)	b,Thickness (mm)	Blade angle (mm)
105	70	2	1	45°
105	70	2..5	1.5	45°

Bottom slitter blades

Outer Diameter	Inner Diameter	B, Width	Large-medium diameter	Small-medium diameter
70	45	10	66	56
80	60	10	77	69
46	25	10	42	35
60	35	9	57	50
90	65	10	87	78

 

Outer Diameter	Inner Diameter	Width	B, Blade width	C, Key width	H, Key width
70	45	5	3.5	10	50
70	45	8	6	10	50
70	45	10	8	10	50
70	45	10	8	\	\
70	45	10	7	\	\

 

Outer Diameter	Inner Diameter	B, Width	Blade width	Large-medium diameter	Small-medium diameter	C, Key width	H, Key width
70	45	10	8	67	59	10	49
70	45	4	2.5	67	59	10	49
80	50	5	3.5	77	65	10	53.8
80	50	10	8	77	65	10	53.8
80	60	10	8	77	69	\	\
70	45	6	4	67	59	\	\
108	80	10	8	105	90	\	\
108	80	20	18	104	90	\	\

Samples


 

Cardboard (corrugated paper) Cutting knives / blades:

BHT's product range is extensive, and includes both standard and customized cardboard cutting blades and corrugated paper slitting knives manufactured using high grade carbon tool steel (9CrSi, SAE52100, D2, SKD-11, 1.2379), stainless steel (420SS, 440B, 440C), high speed tool steel (HSS, SKH-51,SKH-9, ASP-23), tungsten carbide, and other high quality materials.
Backed by more than 20 years of experience in knife and blade production, we will custom manufacture industrial cardboard cutting blades in a variety of shapes and sizes, including straight, circular, pointed tip, toothed, serrated, scalloped, perforated, interlocked and many more to adapt perfectly to different corrugated cardboard machines.
We are experts at custom engineering and production of industrial blades and machine knives according to customer provided drawings and samples. The accuracy is ensured at a thickness tolerance of ±0.001mm and a surface roughness of Ra0.1μm, and a blade bore tolerance of H3. All high accuracy tests are carried out indoors with a constant temperature.
At BHT, we will manufacture your carton cutting blades and knives according to customer provided drawings and written specifications, with a thickness tolerance of ±0.001mm, surface roughness of Ra0.1μm, and blade bore tolerance of H3. All high accuracy tests are carried out indoors with a constant temperature.

Common Specifications	Models
φ230*φ110*1.1	Fosber
φ240*φ115*1	Agnati
φ240*φ32*1.2	BHS
φ250*φ158*0.8	Peters
φ260*φ140*1.5	Isowa
φ260*φ168.3*1.2	Marquip
φ280*φ202*1.4	Mitubishi
φ300*φ112*1.2	Tcy

Samples

 

Split Cutting knives / blades for Lithium Battery Industry

BHT offers slitter blades for cutting and slitting of lithium battery electrodes. These cutting blades are most often made out of an ultrafine tungsten carbide powder and are applicable for cutting different materials, including lithium iron phosphate, lithium manganese oxide, cobalt oxide, and other materials. These blades are compatible with different cutting machines available on the market today, including Nishimura, Yakang, Lange, Hao Can Win, Sharp Maxima or Dudley, and will always meet or even exceed customer expectations.
We also offer custom lithium battery slitter blades according to customer requirements. The service life is generally 80,000 to 300,000 meters depending on the material that needs to be cut. With more than 20 years of experience in the production of industrial blades, our capabilities in customization and processing ensure we can design and manufacture precision industrial blades and machine knives according to drawings or samples provided by the customer. The thickness tolerance is ±0.001mm and the surface roughness is Ra0.1μm, with a blade bore tolerance of H3. All high accuracy tests are carried out indoors with a constant temperature.

Outer Diameter (mm)	Inner Diameter (mm)	Thickness (mm)	Blade angle
100	65	0.7	45°
100	65	2	30°,45°
100	65	1	30°
100	65	3	90°
110	90	1	30°
110	75	3	90°
110.2	90	1	/
110	90	3	/
130	88	1	30°
130	70	3	90°
130	97	0.7	/
130	95	4	/
130	97	1	/
130	95	5	/

  
 

Special shaped customized blade

 

 
 

BHT Clients

 

BHT have exported the products to 65 countries
(Germany, Sweden, Hungary, Italy, Netherlands, Spain, Portugal, Czech Republic, Lithuania, Serbia, Greece, Malta, Austria, Kosovo, Turkey, Ukraine, Albania, Estonia, Belarus, Bulgaria, Bosnia, Croatia, Romania,USA, Brazil, Argentina, Mexico, Bolivia, Colombia, Canada, Peru, Chile, Australia, New Zealand, Rwanda, Egypt, South Africa, Tanzania, Nigeria, Botswana, Mauritius, Russia, Vietnam, India, Iran, Singapore, Uzbekistan, Thailand, Sri Lanka, Bangladesh, Malaysia, Kazakhstan, Philippines, Bahrain, Pakistan, United Arab Emirates, Kuwait, Saudi Arabia, Sudan, Jordan, Oman, Qatar, Syria, Israel, Yemen)